when do buds fatten?

Hi,
I am flowering 4 Serious Seeds Chronics.
they are at 5 weeks flower, they are not as fat as I would have thought.
Today I noticed a few of the hairs are turning brown on each of the plants.
attitude says they harvest at about 50-60 days, so these should be done soon.
T

they usually fattin up the last two weeks and i would add on atlast a week tim to what the breeder says to harvest at