inc 4 times 1 st every 4 rows

Hi! I need help deciphering these instructions: “inc on both sides 2 sts from edge as follows: 4 times 1 st every 4 rows, twice 1 st every 2 rows.”
So, I do an increase 2 stitches in from both edges of a row. Got that. Then I get confused. It sounds like I should do increases 4 times in one row (on every 4th row). So, every 4 rows, 2 stitches in, I do 2 increase stitches one right after another, then 2 stitches from the end I do 2 more increase stitches. AND 2 increases every 2 rows. So row 2 gets 1 inc sts on each side, row 4 gets 3 inc sts on each side, row 6 gets 1, row 8 gets 3, etc. Is this correct?

Hi and welcome!
That is confusing. The idea is to increase at each edge, 2sts in from the edge.
Call the next row, row 1. Increase on rows 1, 5,9,13 and then on rows 15 and 17. You’ll only be increasing 2 sts per increase row.

OK, I think I see. So, for the M & L size, I would inc 1 st on each side, 2 sts in from each edge, on rows 1, 5, 9, 13, 17, 21. Right?

Exactly! You’ve got it.
Enjoy knitting this classic pullover.

Thanks so much!