If you offer free post and ask for $3 extra to be paid for express is it still considered free post?

[sylvee2015]

I have free post on my satchels but if I want to qualify for top rated seller, I need to offer express post. Can I charge  $3 extra for express post and still qualify? I don't sell expensive items so can't absorb the extra cost.

Thanks for any help, Sylvia