Anytime Upgrade to Ultimate is not the same as installing Ultimate. If you have an Ultimate key it will NOT work with Anytime Upgrade. And Visa versa, if you have an Anytime Upgrade key you cannot in the future if you have problems, format your hard drive, install Ultimate and use the anytime key; you must with each reinstall put in your original W7 version (Starter, Home Prem, Pro, etc) activate with that versions key and then reapply the anytime upgrade with its' key.
As Clifford said, Anytime Upgrade can never change the bit version, all you are really doing is unlocking features in the existing OS install that are reserved for higher versions.
So several points to be sure it is clear ...
- if you have an XP/Vista upgrade or full ultimate license you must custom install to use it over a different version.
- if you had an OEM license then it cannot legally be transferred and dies with your old computer.
- any time you want to switch from 32bit to 64bit requires a custom install
- Anytime Upgrades are only for unlocking features in the current lower-end edition installed and require different keys that cannot be used interchangeably with full versions of that higher-end destination edition.