TomD
There are a category of issues that get fervently argued that have to do with the starting with some sort of rhetorical box. In this case bevel angle. If a person believes that a 25 degree bevel angle is straight from god, then there are variations that occur in various characteristics if you say have a main bevel of 5 degrees and a secondary bevel of 25 degrees. Could be good as with a certain knife, or piecing chisel format. Might be a weak edge if one was planning at dragging it through the wood at a 55 degree angle. Same deal make a hollow grind with a 1/4" stone (extremes are just for purposes of visualization, The arguments take flight at much tighter variations like 8" grinders, or bevels that diverge by only a few degrees).

There are a lot of variable, like are we talking about ease of sharpening the bevels , or durability, performance, etc...

In Bill's case, I don't see the issue if the angle divergence is fairly tight. If for some reason he has a big divergence, then I think it isn't a boutique question, it is just a the question of sharpening with secondary bevels which gets hotly argued all the time.

With plane blades what experiments I have done indicate one can do with a far smaller clearance angle than 20 degrees, as little as 5 degrees has worked for me. So in Bill's example, one could just skip to 30 degree, in this case a sharper edge, and then the whole issue would go away because even a 5 degree lower primary would still be 25 degrees, presumably acceptable to even some in the flat bevel society, and the micros would be more obtuse.

I didn't see the point in going into all the details he was, if he was just asking about secondary bevels, that is a simpler question. So I am assuming he is looking for an overlooked issue he might not have read 500 threads on. Which is why I threw out the bit at the end, just to be sure.