I have a H/K AVR 55 on eBay right now which is also rated at 5 x 55 watts. H/K has also been known for putting high current amps in their recievers, meaning they can power low impedence, low sensetivity speakers.
Right before I disconnected the AVR 55 from my system, I hooked my Magnepan MGLR 1's up to it, (4 ohms & 86dB @ 1 watt). I played two whole CDs at a fairly decent volume, and never did the reciever get hot, distort, or clip.
I think your AVR 225 will do just fine with those Fluance speakers.