Whenever they’re “seriously sunk”, you can just look across the valve tips.
When the exhaust are sunk a lot in the chamber side…….they’re just as misaligned on top.
The tip heights showing .020-.030 off on a motor making solidly under 1hp/ci isn’t going to be a major player imo.
Of course……..that assumes they were pretty close to begin with…….which isn’t always the case.
...and yet so many machine shops just "let it go" like that, because "they think" since Chevys have adjustable valves, that everything else can get buy with it , too. But they're so ignorant they don't realize it's killin the Chevys too.