I think you only have to claim that you use AT. For all I know it could include the built-in accessibility settings of Windows itself.
According to https://www.microsoft.com/en-us/accessibility/windows10upgrade all you have to do is say you use AT:
What assistive technologies are eligible for the extension?We are not restricting the upgrade offer to specific assistive technologies. If you use assistive technology on Windows, you are eligible for the upgrade offer.
It worked. Last PC with 10. I was holding off because of the amount of data on the drive. It seems they fixed a bunch of stuff because it went well. Now, to the Family safety settings...