I am not at all an expert so I may be really off base. But it seems to me that you would be doing the increase over 20 rows, so since you are increasing 4 times in all it would be every 5 rows, but it sounds like from the direction it's saying every 6 to me. I don't know if the 34th row or the 6th row is the part that's wrong.
I really don't know.
Sorry I was much help.