Worked in that industry for a few years and 10" is just too shallow for that weight.
I'd be even leery of taking a smaller car across it. I just don't trust manufacturers any more. I've seen 3 month old new concrete tanks break.
As been mentioned before, different tanks, the age of the tank, soil, etc, plays a big part.
With that being said, mine is a concrete tank and it's down about 24" and we have driven the car over it and our lighter JD-770 a few times. We do have another route we made years ago so nothing goes over it now except the mower or our lighter SxS.