Lisa,
If Ella is happy on her current feeding routine, I wouldn't change it. I also use Aptimel and haven't followed their recommendation, because that is all it is.
Calum is nearly 8months and I have JUST dropped to 3 feeds. The main sign to look for from Ella is; a disinterest in her lunch bottle.
If you really want to change can you post your current routine.
HTH's