You're going to get smaller buds the further you go down the plant, majority of the time the smaller branches and nodes are removed to allow the plant to send all the energy up to the top of the plant to feed the main cola, also genetics plays a key role in the size of your buds, amount of light they're getting, your VPD there are many factors to take into consideration, you just want to replicated the most ideal condition as possible...They look good and healthy and they're still plenty of time to bulk up, I haven't seen much more weight in mine in a week or so but I know they're bulking every day your just accustom to see the plants every day and not being able to see the growth taking place