Shortest possible string of functions to give $4x+22$ and $4x+3$

Question

I want to check if my solution to a) iii) and b) iii) are correct.

For a) iii) I got AAMAMA and for b) iii) I got MAMMSD or MMAMAD

I'm not sure if they are the shortest; I just suspect they are because I haven't found any smaller ones.