I guess my question rather was whether they deducted standard shipping or a bit more like in case of OP here?
They deducted the exact rate super saver shipping cost. It sounds to me in this case that the discrepancy might be that the extra $2.30 was on top of the $5. So where it looks like it only cost $2.30 to ship it 3-5 business days, it might have actually been $7.30. Just speculating.