First 2 sets of (12 row) decreases on back done as written. Next 3 repeats (of ‘12’) done as 8s - to compensate for me being a short arse!

Did 5 plain rows after back decreases before starting arm decreases.
Did 26 rows after arm decreases
CO using standard for seams, k2tog for ‘open’ edges

ETA: loved this, it was super warm, but it’s now way too big for me (I’ve changed, not it). Frogged to re-use the yarn