|Just an observation:|
You don't need to check E10 twice, once will do.
Your first check is to see if it is Greater Than 620, if it returns FALSE
then we already know it has to be Less Than 620 or Equal to 620
so why check to see if it is Less Than 620 when we already know it has to be,
just modify your first check to something like: E10>=620.
That changes your formula to something like: