You cannot use a Windows version as a basis for a Mac upgrade without buying directly from Adobe via phone.
Thanks, that is what I was afraid I would hear.
The good news is you have 30 days to return the other version.
I didn't have to return anything because it was a download from Adobe store. For those of you who ever get in this situation, it is an easy fix made more difficult by having to spend close to an hour, or more, with customer service. If you have a product on a mac or pc and want to download a version onto an alternate platform -- mac to pc or pc to mac -- they call it "swapping platforms" and they allow you to do this once without charge. When you start the installation you will get to a point where it says you don't have a recognized version on your computer. At that point, you have to be online with customer service because they will give you the instructions and codes to enter to bypass that and finish the installation. You will also have to fill out a form online while you are doing all this that states you will no longer use the previously installed version.
This swap works for simply transferring the same version from one platform to another, or if you are upgrading at the time you are switching back to a MAC -- Yayyyy!