never mind. found the answer.

[Peterjstock]

I am currently on an old per 3-month $150 plan, which just renewed 5 days ago (and renews in Sept 14)

some of the new  PM plans look better though.

if I Change Now to an alternate plan, what happens to the balance of the prepayment I just made?

[Handy1]

@Peterjstock  you will lose that balance , just pick the option to change plan on renewal that way you won’t loose money and in 90 day are up . You will be switched to the new plan you choose . Changing it immediately and you will loose out on your current cycle . There is no pro rating with PM 

Add pic for illustration 

Change plan in 3 easy clicks

Once you find plan you want be sure to (change on renewal )So you don’t lose money on current cycle