Sleeve pattern question

I’m making a child’s tunic and the pattern says to increase at the ends of every following 3rd row, which to my mind would mean that the increases alternate purl and knit rows. Would that be right? Also, it says to increase to 90 stitches. The entire width of the body is 92 stitches. Does that seem unreasonably wide? Or is that typical? I’ve only done this once before and I can’t remember. THANKS!

Sleeves are always wider than you think they should be, but if it looks like it’s getting too wide, stop increasing.

Every third row would be 1,2,[B]3[/B], 4,5,[B]6[/B], 7,8,[B]9, [/B]so you would be increasing on both sides.