Tension

I’m a relativly new knitter and math hs never been my stong point.
I am trying to get the proper tension for a new project. The original pattern called for aran weight but since I couldn’t find any I did some research and found that knitted worsted could be substituted. The tension called for in the pattern is 18 stitches and 22 rows in a 4" square. I have now worked 3 tension samples, the first wit hthe perscribed needles had one less row but several extra stiches, I went up one mm and got one extra stitch and the right number of rows, the last set came out with the right number of stiches but too many rows. What I wondering is if there is any way to balance this or if it is okay if the number of rows is off as long as the number of stiches is right? The pattern is for a sweater if it makes any difference.
Thank you for your help.

Row gauge is much less important than stitch gauge. Once you’ve begun an item, you can always knit more rows to make it longer, or less to make it shorter, but you can change your stitches per inch.

Go with the needles that give you the 18 st per 4 inches, and when you get close to the armhole decreases you can determine if you need to knit more or fewer rows for the length you want.