I think those shortcuts are often handled by the driver itself, so, it'll already know the required stepping. Another option could be to provide such stepping

I think those shortcuts are often handled by the driver itself, so, it'll already know the required stepping. Another option could be to provide such stepping explicitly as another sysctl. Otherwise, realistically, the keyboard shortcut stepping could simply be assumed to have only 16 variations in the first place, even if you're still using a percentage point through the interface.