PSA/SGC grade est. - Aim high or low?

[scomeau]

Need help w estimating strategy: I'm struggling. I want to grade a bunch of items pre & post war and neither grading company has replied to my question via email. I'm not trying to cheap out, but I don't want to spend $40 for what turns out to be a $99 card.

The problem: Even with PSA's SMR, VCP, eBay as sources for pricing, prices are all over the map based on grade. Makes sense, but grading is hard and it seems to change. I often don't know how to differentiate cards that are between 4 and 7 or higher grades. A 4 from a 7 - probably easy enough, but sometimes 2 or 3 grades are possible.

I'm no pro, but the value difference between 5 and 6 for say, a '56 Topps Williams, is pretty big $180 vs $275. Small potatoes if just one card, but how about a '55 Clemente or a hundred 1956 Topps? I can't tell what I might get back even when I apply PSA's published criteria - such as 'minor edge chipping' vs 'slight notching chipping'. What is 'some loss of gloss' compared to 'average loss of gloss'? Maybe you see a million examples and have a feel, but I find it so difficult.

Submission estimate: So, using the Williams example, if I submit it as a less than $250 service level, and I have mis-estimated, what will the grader do? Should I encourage a generous grade by paying the higher freight?

Your experiences:
Do you get an impartial grade whether you under or over estimate?
Does the grader contact you if you have submitted too low? too high?

Some have advised to estimate enough to cover your investment. I get that, but I'm not dealing. I'm collecting. I want an accurate grade and that's all.

I have a lot of cards (M116's and T202s as an example), whose grade is going to be a guess either because arguable condition or tampering I can't see. And the gap could be wide in $ and grade.

I just don't know what to do. If I submit a nice M116 Plank thinking it's a 6 or 7, but I get a grade of 4 for reasons I can't see, the cost to grade is big. And would they ever give it an 8 if deserved but submitted as a mid-level service.

HELP!