Greetings..
Last year a couple of times during the year T-Mobile offered
1,500 straight minutes for $39.99/mo. Later, they offered 1,000
minutes + nights and weekends for the same rate. It appears that

Just sunk another $50 into my PPD card and soon afterwards decided to
switch to Flex Pay.  Called TM and was told that they cannot transfer
the money from one sim account to the other, and I'd simply lose
whatever dough is in the PPD account.

When you minutes reached the expiration date, do you have any grace period
to add refill to keep the rollover?