Wait, I have to pay the extra $5 every month?
No. Two replies said buy once. I agree that one reply was a little unclear. They've been here a while though so they know the drill. Just didn't type clearly.
Its important to remember your calling minutes are billed per minute for any portion of a minute. So 1 min 56 sec and 1 min 2 sec are both tallied as 2 min calls.
Your usage history will read as follows:
@CharlieR it may also be possible youre on the older "version" of the $15 plan that did not include unlimited incoming calls, if you signed up in say, early 2019.
If so, you can schedule a plan change to the "current" $15 plan.