FOr example, if his meal has 60gm of carbos and his blood sugar is within his target, he would take XX amount of insulin. If his blood sugar is, say 50 points higher than his target, he needs
to know
how to include a correction for that in his dosing.
A person whose ratio is 1:10 "all day long," might begin to adjust the morning Humalog by using a ratio like 1:8 for a few days (and make adjustments for too high/too low starting point).
Hope this helps. Good luck.