Hey there The free data for life plan is not compatible with the T-Mobile One taxes and fees included plan. If you want to keep the free data for life on the tablet, we can file a SIM release form when you switch to T-Mobile One and you can register again on the connect me site to activate the SIM on a prepaid account and keep the free data for life plan.
I just found this question and Answer, but I have a followup question.
Now that T-mobile has discontinued free data for life (as of May 7, 2017),
and t-mobile one is the only plan offered, how do I switch now, but
retain my FDFL on my tablet?