closer nodes happen because of more intense light...stretching occurs when the light is lacking and can not be 'filled in' by adding more after the growth but ya can decrease the distance on new nodes after adding more lumens. i can't see it adding branches in your case this far into flowering but wouldn't worry about it either. the buds will grow out from the buttons you have now and may fill in the entire branch. some strains, like kush, grow shorter flowers tho...more like a pair of thumbs coming off of each node and others grow long, thin, "donkey dicks" and other strains put out "beer can buds". hard to say now what yours are but they're looking good...

if you want to increase bud density and size add a 250w minimum hps...1kw hps if ya have the space. it'll make a big diff at the end...