Am I doing something wrong?

This is my seconds clutch of eggs with the same pairing in the last two years. The babies that hatch out are always so small. They are almost all 5 grams with a couple at 6 grams..This seems small to me but Im not an expert by any means.
I havent had problems with them being unhealthy or not eating but they come out of the egg so skinny and small.
Ive heard that Miami phase tends toward small babies(not sure where I read this) is this the case?
They were incubated around 80- 81 degrees, its been 65 days and most are out of the egg. Last year I incubated at 82 -83 degrees and they hatched at 58 days, so reduced the temp a bit hoping for a longer incubation and larger babies, but it didnt make a difference.