PSA Submission Levels

[GasHouseGang]

I have a question regarding PSA, or any grading service really. Does the submission level you submit a card at, ultimately help determine the grade? I ask this, because there are cards that can easily cross the submission level based on what grade the card comes in at. Suppose I submit a 1956 Mantle, and submit it at Express level that PSA uses and put on the submission form a value of $1200, thinking it's at least a PSA 7. Express is for cards up to a value of $1999. But I really hope it will be a PSA 8 which would raise the value beyond "express" level service to "Super Express". So I should have paid PSA $60 for grading instead of $35 if it's a PSA 8. So my question is, do PSA graders say to themselves, "Well, it's probably an 8 but since he only used "Express", I'll grade it a 7." Am I cutting my own throat by choosing the lesser level of service? This is not meant as a PSA bashing thread, just a question about how these grading services really operate.