Class A vs AB

You mention the level you play at but that's an average. If your music is dynamic with large momentary swings you need power to not clip them. And peaks can be 10, 20, even 30 dB and you will be out of class a.

By the way, almost no push/pull(non single ended amp) is really pure class A. It's very rich class A switching to class B. For instance Nelson Pass's class A amps have a class A power rating but they typically have 2 to 3 times that power where they switch to class B momentarily so the peaks are clean. 

I wouldn't worry about staying class A. Stay with your amps and they are probably class A over 95% of the time.

This link might provide some context.

I would be mostly concerned that my amp would sufficiently deliver the power so that I could easily listen at the levels I want.  As @hjdca said, you could give it a try.  There is nothing wrong with the sound of a good Class AB amp and your amp was meant to cross seamlessly into AB as needed.

You’ve got some really good speakers, so I think the much bigger question is why you’re considering the 1528s? The amp crossing to AB is a relative rounding error here IMO, and by far the biggest variable is the sonic character differences between the speakers and which is more to your liking. 

I have owned a couple of AB Pass amps. The most recent an X350, I could never tell when it switched. 

What musicians do you listen to?  I listen to a variety of music and not much of what I consider rock is a high quality recording. Some of it is.  I'm listening to Riverside currently and it's pretty good.