No, Brian; that wouldn't be a safe assumption. The actual listening level apparently hasn't been measured, and that's necessary to know the actual power used by the speakers. If some or all of the observations are real rather than illusory(which is often the case with us)there's a strong probability that the listening volume was at least slightly higher. Amplifiers only add more voltage from their power supply section to the incoming voltage from the source material at any instant to make it drive a speaker loud enough to be heard easily(typically pre-amplifiers increase voltage 4-5 times and amplifiers 25-30 times). If they don't make it louder, they don't have any magical ability to somehow make the sound better at the same level. At a comfortably loud listening level(say mid 80s of dBs)speakers of typical sensitivity, such as the Axioms, use about 1 watt. How much more is needed for brief peaks depends on the source material. Some pop material is almost uniformly loud and has a dynamic range approachng zero. 2 or 3 watts might be the most used on such material. In contrast, some highly dynamic material, such as a few of the classical recordings I have, may have brief peaks as much as 20dB above the average and would require about 100 watts for that listening level(which I rarely actually use).
So no, there's no clear indication that any "extra" power over what your receiver could supply anyway was used.
