Small for 3 weeks flower?

I have compared my grow to others that have been flowering for the same length of time. How do they look? Should the plant/buds be bigger by this time? I figure the stretch period is over so does that mean my tops wont get any taller? The tallest top is only about 8" above the screen, the rest are around 4-5" above.

400w HPS 12" away
Temps between 68 - 85
2 purple paralysis plants in a 18" x 26" scrog
Soil in a 3 gallon pot
Nutes: Schultz Plant Food 8-14-9 every other watering
Day 28 of 12-12

How does it look?

Looks great, keep on doing what you're doing. Not much taller, no.