The push-up and sit-up limits ARE really low. Remember, unlike the CFA, which is pass/fail, the PRT is graded. The numbers shown on the USNA link from my earlier post are the absolute lowest numbers to not fail a PRT, IOW, those numbers are low D's.
"Perfect" scores for pushups would be 85 for women or ~100 for guys. A "perfect" sit-up score would be ~100 for either gender. After those events, you have to pass the 1.5 mile run time. Each part counts 1/3 of your score, but you must pass each section, so you can't max two and totally bomb the third.
If someone does flunk the PRT that's held near the start of each semester, they have to do a second one that same semester, and they sometimes have to do remedial workouts under supervision. You really don't want to do that.....