Ah, that makes much more sense. I would guess from reading that, that T-Mobile uses a product from Experian where the credit approval process happens entirely on Experian servers and not within T-Mobile's system or T-Mobile uses a data warehousing solution from Experian, where the data is theirs, and it is on dedicated servers, but they are housed at Experian and not T-Mobile.
There are reasons that a body stays in motion
At the moment only demons come to mind