More power for moderate listening levels?

It doesn't work that way, and we don't need to know anything about your room. Geez Louise! This is because amps and power don't work anything like the way the vast majority thinks they do. Its perfectly possible you could find a lower power amp that sounds hugely better at both low and high volume. Class A has nothing to do with it either. These kinds of generalities sound all logical and certain but they break down real fast the minute you hook up the exception to the rule.  

You don't mention the power of your Class A amp. But that doesn't matter either. Unless its like single digits. Because once you get up around 20-50 watts then its not the amp. Its the speakers. If yours are low sensitivity (92dB/1w/1m) then it very quickly becomes almost impossible to find an amp powerful enough to play them loud. Particularly if they are below 90, then you can pretty well forget about it. This is why you see all these guys searching around for the right amp. Its not the amp. Its the speakers.

LOL!!! I was writing while you were writing. First thing I checked, your speakers are hopelessly inefficient. Harbeth has the hutzpah to say they are easy to drive! Not at 86dB they're not! Doesn't matter the impedance! Now you know why you see all these guys in love with their speakers searching searching searching for the amp. Its not the amp. Its the speakers. 

Also notice I didn't need any details. I worked this all out simply based on your first post.

Thanks for the responses. 
The assumption is that the lower powered amplifier drives the speakers just fine at moderate listening levels. My listening says yes.
At the SAME volume, will a higher powered amp improve the sound quality?

OP  That WAS your question (In your second post). I fail to see any progress towards an answer being made by yammerng about "it "

brianbiehs OP6 posts11-03-2020 10:51am
"...."At the SAME volume, will a higher powered amp improve the sound quality?"

Always nice to have extra power (headroom) on tap to handle the dynamics and the INT-250 @ 250wpc would certainly do the job, as Pass indicated. The INT-25 @ 25wpc, however, is Class A vs INT-250's Class A/B, and the sound quality at moderate power levels may be better on the smaller amp. The only way to find out is to A/B the two in your system.