Help with sweater pattern

[Diane321]

Hello, I am knitting the Allegra Jacket from the Naturally Caron.com website. I would greatly appreciate if someone could make this section of the pattern a little more clear to me. Here go's:
This sweater is knit in one piece, starting at the right sleeve.
Sleeve Shaping
(RS) Inc 1 st each side this row, then every 4 rows 6 (8,13,15,20) times, then every 6 rows 10(9,6,6,2)times-91(97,103,109,115)sts.
Does this mean I knit 4 rows and inc on the 5th or does this mean I inc on every 4th row? This wording is sooo confusing to me. Could someone please quide me in the right direction? Thank you so much for your time and expertice! Diane

[MerigoldinWA]

"then every 4 rows" I would interpret as to increase on the 4th row, so count 3 and increase on the next one. "then every 6 rows" I would take to mean on the 6th row, knit 5 and inc on the next one.

[suzeeq]

Inc on this row, call it R 1, then on R5 which would be the 4th row, and every 4th row after that which would be the 9th, 13th, 17th, etc. until you've done the right number of rows, then switch to every 6th row