to answer ur question, YES, they do fatten up towards the last 2 weeks of flower, u will not be able to tell by the eye if the buds are done, u will need to go to radioshack and get a 13$ scope 30-100x scope. its cheap and works great, u are looking more towards 40/60 amber trichomes. really it just sounds like u were having a nitrogen def. thats common when flowering, but not if there is alot going on. add some nitrogen and u will be fine, if the problem proceeds, its because u have burned them with excess nutes. put the plants as close to the lite as possible, but make sure u are checking temps at the TOP OF THE CANOPY so its not too hot, u are looking to keep it at 85 degrees F max.