I don't disagree with any of that. But the glass in question was not a regular and uniform dished shape. If it were it wouldn't be as much of an issue, agreed. My main issue is I like to be able to go from hone to film to whatever medium without adding extra work for myself.

In a case such as the pieces of glass that I got, they did not come close to hitting uniformly across an edge that was finished on a flat stone - that's how I found that the glass was so far out in the first place. Initial honing on a 12u film only hit in a few places, and at differing parts of the bevel. Like many others, I had assumed the glass would be flat enough as is. It wasn't, so I flattened it. I could have done a non standard stroke to hit all along the edge also, but that's not the way I do things unless I have to. Say on a razor that has a bent spine, et. al.

You agree that it's less effort and work as well as easier to hone on a flat surface - that subsequent honing on a flat surface like a stone would be easier and less work if the glass was flat is all I was saying in the first place. I mentioned that in my first or second post in this thread IIRC.