Average mark using coefficient

Hi!
Thanks for this app, you've done a great job and I'm grateful for my bag'll be lighter thanks to you!
There's only one thing I can't do with your app but maybe I just don't know how to.
In France we use coefficients like 0,5; 1; 2 etc...
For exemple students can have a coefficient 1 mark and a coefficient 2 mark meaning that the coefficient 2 mark will count twice in the average mark.
Is it possible to create an average mark with that kind of coefficients? I've tried using the % of course but I can't find the correct way to put it, especially when I don't always have the same number of marks for the average mark at the end of term.
I hope it's clear and that there's a solution.
Thanks again.

Hi there Lady Vain,
I'll send you a private message this afternoon with some questions so we can sort this out, if not in this version , we'll make it work for the upcoming next!
Thanks for your comments.