We're focusing more on the mix down part as that's more objective and less subjective and Landr/Ozone already exist so we're not starting off specializing in mastering. With additional time/funding what I'd like to build is the ability to let the user specify a specific reference track and not just an artist for the AI to use as a reference.
To your question though, it's a chatbot so tell it you want your track to sound like eg Polo and Pan, it'll look for ways to enhance it in their style rather than a simple small/medium/large knob.
The problem I have with the AI mastering is it seems to be a bit clumsy with making the master fit the song. A lot of these tools just have simple buttons like "low, medium high", and seem to default to really squashing the dynamics to achieve maximum loudness. I have worked with both human mastering engineers and AI mastering, and I would say a decent human mastering engineer is noticeably better at feeling out the songs and finding the right balance.