CC progression question; what works best?

For those actually doing CC: when you’ve met a standard such as the intermediate standard for kneeling pushups (2 sets of 15 at the 2-1-2 tempo) and you’re looking to add reps, have you found it more effective to first add a rep or two to the first set of 15 while repeating the second set of 15, (e.g. 17 for set 1, and a repeat of 15 for set 2) or distribute the reps across the two sets, e.g. 16 and 16? Or have you found that it makes no real difference? Likewise, after meeting an beginner standard (e.g. 1 set of ten) has experience shown it to be best to hold the 1 set of 10 constant and build up a second set until reaching the same 10 reps, or increase set 1 to maybe 12 reps, and do what you can on set 2, ultimately trying to add a rep or two to both sets until hitting 15 and 15?