This is more than flat enough, by any definition:
https://accuratesound.ca/product/raal-requisite-ca-1a-filterset/
By my definition, exploiting up to +/-2.5dB deviations (with my own measuring method) from a ruler-flat is OK.
As it was noted by Immanis users, it shows great differences between DACs, amps, recordings, so it's not overdone in a way that will make it sound genre specific.
Now, you will inevitably see measurements floating around that will go over that target number, but those measurement will not explain why it shows such great differences in components of the chain and why it doesn't really prefer any genre.
Anyhow, the demo unit for Warsaw AVS has been sent yesterday, so you have a chance to evaluate them yourself, at AVSor later.
Whatever I tell you, will not have anything to do with whether you will like them or not, but please let me know how they were for you, once you have a listen.