Fewer reps with more weight

For a change I moved from 15 reps to 8 reps and moved to the next weight block.
I want to keep increasing plank time.
17 free weight exercises for toned arms

The jar idea of moving weight by marbles from the pre to post is a neat idea. But all weight is not the same. There are certain points which mean different things. I am at about 137 now.
132 is pre 2nd pregnancy weight
123 is ideal BMI
120 is the least I weighed after pregnancy
110 is pre 1st pregnancy weight