Object models when moving between Windows and Mac

I'm running into a challenge -- I need to create a spreadsheet that runs with VBA on both Windows and Mac. 

When I create a new spreadsheet in Windows, I can go ahead and add the "Microsoft PowerPoint 16.0 Object Library" - add my code and it runs fine.  When I then open up this spreadsheet on the Mac - it downgrades the object library to "Microsoft PowerPoint 14.0 Object Library".  The code still runs fine.

The problem occurs when a user updates the excel file on the Mac and a Windows user tries to open it back up.  The reference library gets messed up. On the windows machine it has the Microsoft PowerPoint 16.0 Object library de-selected, and instead, there's a checkbox in the "MISSING: Microsoft PowerPoint 14.0 Object Library".  The code will now not run until I manually go deselect that box and re-add the PowerPoint 16.0 object library.  As I need users in both platforms sharing this sheet it's a bit of a problem... 

Is there any way to work around this?  Thanks.