This page on the Intune console needs to be redesigned - I don't think it's changed much if at all since its original incarnation - so that it presents the ACTUAL behavior instead of simplified "delete devices after X days". The nuance presented here is completely lacking from the page itself, and there's not even a link the documentation (not even hidden inside any of the tiny question-mark circles!).
https://intune.microsoft.com/#view/Microsoft_Intune_DeviceSettings/DevicesMenu/~/deviceCleanUp
Not to mention, of course, that the docs page is ALSO in need of a lot of help! It needs to have its own page, and the contents of this blog post and pertinent details from answered questions should be added as well.
Help your customers to understand, I'm sure the support calls will drop for questions related to features if the actual info about those features is 1) immediately accessible and 2) actually available.
Props to the author here for sharing these details - if only we had such background info about the rest of the product.