I think your reaping the benifits already, She's going 5-6hours overnight therefore getting in all her callories in the day.
I had two very different feeders' one who was like this seemed to feed all the time (it did carme down around 8week's but some take a bit longer), but then did 5hours at night. Seconed one who was a 3hour feeder (with some cluster feeding occasonaly) from almost day one. But he was still feeding every 3hours for months yes that's EVERY 3hours no long gap at night. (Good job we co-sleep)
Go with the flow they are so little for such a short time it'll pass before you know it. Then you'll be reapping the rewards of all those milky smiles