Sounds like what Caeden has starting doing. I usually let him go till he starts coming off and on and then switch sides and he typically nurses twice as long there and then when he is done I will offer the first side again. He often takes it and nurses anothre 5 minutes or so.
I also switch which side I start with so at least every other feeding I know it is getting completely emptied!
So far this is working for us, he is going longer between feeds too - I can get 3 hours easier now and before I was struggling to get 2 - 2 1/2.
I would go ahead and switch sides and see how she does!
Also - at night he only takes one side at a time unless he poops and I have to change him and start over. But then he is like half asleep anyway and so he nurses well and doesn't get frustrated when it slows down!