diff --git a/eos/saveddata/module.py b/eos/saveddata/module.py
index 53f611ddb..8d4a6d5af 100644
--- a/eos/saveddata/module.py
+++ b/eos/saveddata/module.py
@@ -239,8 +239,15 @@ class Module(HandledItem, HandledCharge, ItemAttrShortcut, ChargeAttrShortcut):
 
     @property
     def modPosition(self):
-        if self.owner:
-            return self.owner.modules.index(self) if not self.isProjected else self.owner.projectedModules.index(self)
+        return self.getModPosition()
+
+    def getModPosition(self, fit=None):
+        # Pass in fit for reliability. When it's not passed, we rely on owner and owner
+        # is set by sqlalchemy during flush
+        fit = fit if fit is not None else self.owner
+        if fit:
+            return fit.modules.index(self) if not self.isProjected else fit.projectedModules.index(self)
+
 
     @property
     def isProjected(self):
@@ -570,7 +577,7 @@ class Module(HandledItem, HandledCharge, ItemAttrShortcut, ChargeAttrShortcut):
             current = 0  # if self.owner != fit else -1  # Disabled, see #1278
             for mod in fit.modules:
                 if (mod.item and mod.item.groupID == self.item.groupID and
-                        self.modPosition != mod.modPosition):
+                        self.getModPosition(fit) != mod.getModPosition(fit)):
                     current += 1
 
             if current >= max:
diff --git a/gui/fitCommands/calc/module/localAdd.py b/gui/fitCommands/calc/module/localAdd.py
index 259a4cc95..ef21348c7 100644
--- a/gui/fitCommands/calc/module/localAdd.py
+++ b/gui/fitCommands/calc/module/localAdd.py
@@ -34,14 +34,18 @@ class CalcAddLocalModuleCommand(wx.Command):
         if newMod.item.category.name == 'Subsystem':
             for oldMod in fit.modules:
                 if oldMod.getModifiedItemAttr('subSystemSlot') == newMod.getModifiedItemAttr('subSystemSlot') and newMod.slot == oldMod.slot:
+                    if oldMod.itemID == self.newModInfo.itemID:
+                        return False
                     from .localReplace import CalcReplaceLocalModuleCommand
-                    self.subsystemCmd = CalcReplaceLocalModuleCommand(fitID=self.fitID, position=oldMod.modPosition, newModInfo=self.newModInfo)
+                    self.subsystemCmd = CalcReplaceLocalModuleCommand(
+                        fitID=self.fitID,
+                        position=fit.modules.index(oldMod),
+                        newModInfo=self.newModInfo)
                     return self.subsystemCmd.Do()
 
         if not newMod.fits(fit):
             pyfalog.warning('Module does not fit')
             return False
-        newMod.owner = fit
         try:
             fit.modules.append(newMod)
         except HandledListActionError:
@@ -49,7 +53,7 @@ class CalcAddLocalModuleCommand(wx.Command):
             if self.commit:
                 eos.db.commit()
             return False
-        self.savedPosition = newMod.modPosition
+        self.savedPosition = fit.modules.index(newMod)
         sFit.recalc(fit)
         self.savedStateCheckChanges = sFit.checkStates(fit, newMod)
         if self.commit:
@@ -61,9 +65,9 @@ class CalcAddLocalModuleCommand(wx.Command):
         # We added a subsystem module, which actually ran the replace command. Run the undo for that guy instead
         if self.subsystemCmd is not None:
             return self.subsystemCmd.Undo()
-        from .localRemove import CalcRemoveLocalModuleCommand
         if self.savedPosition is None:
             return False
+        from .localRemove import CalcRemoveLocalModuleCommand
         cmd = CalcRemoveLocalModuleCommand(fitID=self.fitID, positions=[self.savedPosition], commit=self.commit)
         if not cmd.Do():
             return False
diff --git a/gui/fitCommands/calc/module/localClone.py b/gui/fitCommands/calc/module/localClone.py
index dbe6ce0d8..d94180666 100644
--- a/gui/fitCommands/calc/module/localClone.py
+++ b/gui/fitCommands/calc/module/localClone.py
@@ -31,7 +31,6 @@ class CalcCloneLocalModuleCommand(wx.Command):
             return False
         if not fit.modules[self.dstPosition].isEmpty:
             return False
-        copyMod.owner = fit
         try:
             fit.modules.replace(self.dstPosition, copyMod)
         except HandledListActionError:
diff --git a/gui/fitCommands/calc/module/localReplace.py b/gui/fitCommands/calc/module/localReplace.py
index bf9e1717f..4452381f5 100644
--- a/gui/fitCommands/calc/module/localReplace.py
+++ b/gui/fitCommands/calc/module/localReplace.py
@@ -85,7 +85,6 @@ class CalcReplaceLocalModuleCommand(wx.Command):
             pyfalog.warning('Module does not fit')
             self.Do()
             return False
-        oldMod.owner = fit
         try:
             fit.modules.replace(self.position, oldMod)
         except HandledListActionError:
diff --git a/gui/fitCommands/gui/itemsRebase.py b/gui/fitCommands/gui/itemsRebase.py
index 437c2c151..00cbae666 100644
--- a/gui/fitCommands/gui/itemsRebase.py
+++ b/gui/fitCommands/gui/itemsRebase.py
@@ -27,7 +27,7 @@ class GuiRebaseItemsCommand(wx.Command):
                 cmd = CalcRebaseItemCommand(
                     fitID=self.fitID,
                     containerName='modules',
-                    position=mod.modPosition,
+                    position=fit.modules.index(mod),
                     itemID=self.rebaseMap[mod.itemID],
                     commit=False)
                 self.internalHistory.submit(cmd)
@@ -35,7 +35,8 @@ class GuiRebaseItemsCommand(wx.Command):
                 cmd = CalcChangeModuleChargesCommand(
                     fitID=self.fitID,
                     projected=False,
-                    chargeMap={mod.modPosition: self.rebaseMap[mod.chargeID]})
+                    chargeMap={fit.modules.index(mod): self.rebaseMap[mod.chargeID]},
+                    commit=False)
                 self.internalHistory.submit(cmd)
         for containerName in ('drones', 'fighters', 'implants', 'boosters'):
             container = getattr(fit, containerName)
@@ -53,8 +54,14 @@ class GuiRebaseItemsCommand(wx.Command):
         for cargo in fit.cargo:
             if cargo.itemID in self.rebaseMap:
                 amount = cargo.amount
-                cmdRemove = CalcRemoveCargoCommand(fitID=self.fitID, cargoInfo=CargoInfo(itemID=cargo.itemID, amount=amount))
-                cmdAdd = CalcAddCargoCommand(fitID=self.fitID, cargoInfo=CargoInfo(itemID=self.rebaseMap[cargo.itemID], amount=amount))
+                cmdRemove = CalcRemoveCargoCommand(
+                    fitID=self.fitID,
+                    cargoInfo=CargoInfo(itemID=cargo.itemID, amount=amount),
+                    commit=False)
+                cmdAdd = CalcAddCargoCommand(
+                    fitID=self.fitID,
+                    cargoInfo=CargoInfo(itemID=self.rebaseMap[cargo.itemID], amount=amount),
+                    commit=False)
                 self.internalHistory.submitBatch(cmdRemove, cmdAdd)
         eos.db.commit()
         sFit.recalc(fit)
diff --git a/gui/fitCommands/gui/localModuleCargo/cargoToLocalModule.py b/gui/fitCommands/gui/localModuleCargo/cargoToLocalModule.py
index dee4d5bf2..eacce7aa8 100644
--- a/gui/fitCommands/gui/localModuleCargo/cargoToLocalModule.py
+++ b/gui/fitCommands/gui/localModuleCargo/cargoToLocalModule.py
@@ -56,7 +56,7 @@ class GuiCargoToLocalModuleCommand(wx.Command):
             commands.append(CalcChangeModuleChargesCommand(
                 fitID=self.fitID,
                 projected=False,
-                chargeMap={dstMod.modPosition: self.srcCargoItemID},
+                chargeMap={fit.modules.index(dstMod): self.srcCargoItemID},
                 commit=False))
             success = self.internalHistory.submitBatch(*commands)
         # Moving/copying/replacing module