Crossfit

Regarding reps, I guess it's a thing of calibration. Usually, you do less pull-ups than push-ups, because the muscles are smaller and get tired more easily. The same go for air squats, where the quads are massive in comparison to your pecs and delts. Unless you are skipping leg day every day and you're shaped like an inverted triangle, then it can be whatever.

It reminds me to this chart of cardio conversions. There might be something similar for own weight exercises depending on the muscle group.