Pre-digital typeface drawings question.

I discovered once you go beyond a certain weight towards the dark end you're forced to expand rather than simply add weight on the inside and at this point you actually do need extra points to increase the weight optically while expanding as little as possible.

In other instances I've seen there are either a few extra points placed at strategic places for extra control or they seem to be placed more or less randomly, which is due to font conversion or bad use of anchor points.