So say she is up at 7, does 1.5hr A then 1hr45 nap, eats at 10.15, 1.5hr A, 1hr45 nap, eats 1.30, 1.5hr A, 1hr45 nap and eats at 4.45. I'd probably try to get her down for a CN by 6pm but just let her have 20 mins and then do her BT milk at 7 and BT 7.20. That would be based on knowing that she would probably need about an hour of A time after a 20 min nap. I wouldn't let her sleep for 30 or 45 mins because I would know then that would push BT too late as I wouldn't expect her to go to bed less than an hour after she last woke.
It is a bit of trial and error really so if I found that wasn't working and she either needed longer awake before BT to be tired enough to sleep again or that she didn't want a CN at that time or she didn't want to eat again so soon after the 4.45 feed or that too much day sleep seemed to mean she didn't sleep well at night etc then I would probably start waking her after 1.5hrs for one or more of the naps to bring the feeds and A times forwards.
For us A times lengthened and that is how we moved feeds later. I never really worried about whether it was a 3 or 3.5 or 4hr EASY as such. When I got to a stage where my boys didn't want to take that last catnap of the day or it just got too late to fit it in before our desired BT then I knew we had to drop it and I started pushing the first A times and letting them sleep longer (if I had been waking them) so that the first few naps fell later in the day. It is all just a rough guide really. All babies are different and very few will do identical A times and nap lengths throughout the day. You might get 1.5hr A time at first and a 1hr45 nap but then the next nap is only 1.5hrs or less so those second and third feeds are only 3hrs apart. Just before they dropped a nap our day got longer and BT moved later. Then when that last nap was gone or moved to a CN I brought BT forward again to avoid a too long A time before BT.
The important thing about EASY is that it is a flexible routine that follows your baby's cues not a rigid schedule that dictates what time she can eat and sleep. It doesn't matter if every day is the same or not, it probably won't be.
If you think she is having a growth spurt and you think you need to actively work in 5 evenly spaced feeds to maximise the amount she takes then by all means wake her at the 3hr point to feed. If all is going well though then just stick with what you are doing