i've actually been wondering the exact same thing- she only feeds on one side and for about 10-15 minutes every 3 hours (with a cluster before bed). i used to try to get her to eat more and take the other breast, but she would scream! she would act like she was hungry- latch on quickly and suck, but then would spit it out and scream. i thought something was wrong with my milk or something. but since i've given up on trying to get her to eat more, and just let her feed until she comes off the first side, it's been much easier. she must be getting enough- plus she's gained almost 5 lbs since birth! if she hasn't eaten enough, she will just let me know within a half hour, in which case i'd feed her again thinking that she must not have had a good feed. your lo is just a very efficient eater!
as far as the EASY routine, i just had to adapt to her. i have to put her to bed as soon as she gets tired, even if it means that it's only been 1/2 hour of activty...