Changing sizes in directions

I’m knitting a child’s vest. The smallest size in the pattern is size 4. I want to make it size 2. The directions gives size 4,6,8,10, 12. The # of stitches cast are all 4 stitches apart, starting with 38. I assume that I cast on 34. The problem is with the bind off at the arm hole. They say 3 stitches for sizes 4,6,and 8. Should I do 3 stitches?
It’s a bulky vest, with the gauge 3 st= 1 inch.

Thanks for the help.

Another, simpler way to down-size a pattern is to use smaller needles. This way you can follow the pattern as written, yet end up with a smaller garment.

If you don’t want to do that, I would do what you’re already doing. Check out the differences between the other sizes and work from there. If they all say the same, I’d go with that. Better yet, wait until you get to the armhole and see if three would be appropriate.