It depends on the yarn you're using. 80 stitches might be enough with a heavy yarn, but not with a thinner yarn.
When you knit in the round, you're not really knitting circles--you're really knitting a long spiral. That's why there is a bit of a jog where one round ends and the next begins. It's normal.
A true ladder looks more like a run in a stocking. Those generally don't happen with circs.