Deadline to postpone is already past. That being said, all you can do now is BR like a madcunt. Drill until you can do those 70's tests @ 100%. It's fine if you have to straight up to redo them.
I would just BR/Review all the stuff in the 70's to really get a feel for HOW you are making mistakes and WHY you did not get questions you "usually" get right. That has made a big difference for me in similar situations.
Yes, now! You have a few weeks until the September exam. Coupled with the fact that you should not be going PT crazy the week of the test, you'll want to start PTing with the 70+ exams.
What else is going on? Is there a particular section you're losing points on? Have you started running out of time on sections you were finishing before? Are you taking the tests sequentially and just got into the 70's?
@Tina, replying this late may be really weird but I didn't see the notification for some reason! I did do Prep tests in the 40's as well, and my score during those was anywhere from 160 - 165, so I didn't really expect what happened in early 70's!
Just an update... I have come back to the 165 - 168 range in the later 70's i.e. PT 74, 76, 77, 78. So I no longer know what to think :/ (skipped 75 for December just in case I need it)