Sum is off by .01 according to calculator

[Cnuessle]

This pricing calculator almost finished and as I test it there is a rounding issue somewhere that I cannot seem to find. Hoping a new set of eyes can point out something I seem to be missing. Every helper cell that is calculating is showing the correct number in that cell and in the sum cell it is calculating each helper cell correctly however the final sum is .01 off
If I round the cells the helper cells that would correct the .01 difference then the sum cell creates other test sums as .01 over.
I'm not sure where this is going wrong. Can someone please help.
Please see workbook the correct are shown as well in correct. These numbers are based on the Green totals with their calculation compared the those same equations on a calculator...