Hi Chris,
There shouldn't be any problem while upgrading and switching the OS.
If you want to upgrade from Acrobat10 Win to Acrobat 11 MAC, you can do that. Its called Cross Platform Upgrade.
You need to contact adobe for that. It cannot be done online from adobe website.
For the best assistance, I recommend our chat support atGet help with orders, refunds, and exchanges
Our chat representatives can provide a personalized experience to resolve the issue you have described.
Regards,
Rave