Generally, as I understand it - a single-ended tube amp uses only one tube to amplify the signal per channel. In your case, I believe it's a PSE or parallel single ended configuration. It would be best to ask your Ayon dealer or the mfg co more.
A class A tube amplifier refers to how the tubes are biased and operate, not the configuration. In Class A, the output tubes are always conducting, even when there is no output signal.
Others may explain it differently, and while I'm not a tube amp circuit guru or anything like that, I have spent some time doing homework on what helps an output tube to operate in its "optimum operating window". i.e. People install KT150s in older amps not designed to run them properly, with insufficient plate voltage, and the tubes don't sound their best. Appears yours IS designed to run the newer line of KT tubes which is great. Using the right tube for a given amplifier circuit design is what's more important, or what I believe so far. :)