My Boys and School

I have mentioned before that I homeschool my boys.I do a different type of school that is computer based and I will be following up with a review about it soon.My boys attend ECOT and I recommend it for anyone that wants to teach at home but with a set schedule and lessons.Anyway,my oldest Gage is 8
and is in 3rd grade.This semester he received 4 A's and 1 B on his report card.My youngest boy Aiden is 6 and in second grade(he skipped first grade) and received 3 A's and 1 B.Needless to say I am thrilled with them.I am VERY strict about their grades and do not accept anything below a B without consequences.I have been told I am too hard on them,but I never listen.However I though I would ask you what you think.

Do you require certain grades from your kids?
Do you have restrictions or punishments for not getting those grades?
If you homeschool do you have a grade system ?

I am curious how others feel about this .I am hard on my kids because I know what it is like to work for everything and I want them to have a  head start in life .