Dana
Have you tried 4hrs between feeds? If so, did she eat better/more? All Lo's are different, my DS changed to 4hr EASY when he was 3 months, he did the same; playing with feeds at the 3 hour mark, did this for a week - I began to dread feeding time. After newyear I decided to follow his lead for feeds, he wanted fed every 4 hours, although this meant I dropped a feed (I don't do a d/feed) so it mean 4 bottles instead of 5 during the daytime. He wasn't ready for the extra A time but we got there.
If I had kept him on a 3 hr EASY, we still would have been fighting yet!! Remember EASY is not always EASY, we sometimes do ESAY but more often then not EASA all day. I think as long as you don't start a situation where she eats then sleeps, I would go with your instincts I see if it works better. EASY will come back, I remember this time played havoc with our routine, but we got it back in the end. 3 - 4 months is a time for HUGE changes.