That sounds like something I can do (unlike my attempts to introduce mythic leadership and make an eidalon have Mythic Tier 5 out of curiosity
).
I'm afraid I can't help you on the reasoning I've just been looking at the alternate capstones for various classes and that was the most recent I'd seen on the SRD. So I used it as an example, It's from
https://www.amazon.com/gp/product/16...b602c0e3138479 if that helps.