CAM HELP NEEDED!

Hey rumble,
Is the ABDC spec for roller cams always measured at .050? In the comp card above it shows 38, and searching others on their website always seem to show a ABDC number in the 30's verses the 50/60 for a flat tappet hydraulic. Always wondered about this.
This has me wondering as well. The cam companies do things I don’t always understand and wonder why they supply what is ether a lot of info or not a lot of info.

Why they do what they do is a mystery to me.
I know we’re talking cams here but what’s your thoughts on zero deck, .03 Head gasket and closed chamber heads?
.030 clearance? Factory did less. IMO, that’s fine. It helps create a good agency area.