I do that to some extent except I don't write it down. If I can't remember it then I can't use it when I'm hunting - no time to get a notebook out when I see something I want to shoot.
Are you using an FFP scope? I didn't see if you mentioned adjusting for different power settings or not. Most of my scopes are SFP so I tend to stick to specific power settings for each distance so I don't need to remember how to calculate the differences for each scope. I just oust got some FFP scopes so I'm enjoying not having to worry about that...
The other thing I do (if I'm not sure of the drop) is try to cover my target with two (or three if possible) mil dots but that only works for hunting where it's only important to hit the kill zone.