Too many zeros?...

Ok, this is what the instructions say on the actual usps module which are different from the instructions found on the file included with the module:
"Volume is set in digits 6-11 after the decimal point in the products weight field.
eg: Product A weighs 1.25lb and is 689.3 cubic inches so,
Product A Weight: 1.25000068930"

My weight is for a 5oz item (0.3125) 9 cubic inches.
So if the volume is supposed to be set on the 6 digit after the point, it should be 0.3125009 (right?)
So I tried that and same result.
If I add 2 products to the shopping cart everything shows fine, as soon as I add one more product the small, large and medium rate options disappear.