Sales Order Tax Calculations

We currently use Web Services to create customer and salesOrder records inside NetSuite from our network of websites.  When the orders are sent to NetSuite an e-mail notification generated from OUR system, as well as an e-mail notification generated from NetSuite gets sent to my address.

I have noticed there are several instances in which sales tax calculations are NOT happening consistantly.  Below I have included a table of the sales tax calculation being made by our websites versus NetSuite:

[NOTICE THAT THE "TAXCALCULATED" COLUMN DOES NOT PROPERLY ROUND IN THE "TAXASSIGNED" COLUMN]

 <span style="font-size:'"1"'"><span style="font-family:'"Lucida Console"'">orderType subTotal shipping discount taxAssigned total taxCalculated   websiteOrder 31.5  6.38  6.38  2.44  33.94 2.44125  salesOrder 31.5  6.38  6.38  2.45  33.95 2.44125  websiteOrder 55.85  6.38  6.38  4.05  59.9 4.049125  salesOrder 55.85  6.38  6.38  4.05  59.9 4.049125  websiteOrder 61.89  7.18  7.18  4.49  66.38 4.487025  salesOrder 61.89  7.18  7.18  4.49  66.38 4.487025  websiteOrder 26.94  6.38  6.38  1.95  28.89 1.95315  salesOrder 26.94  6.38  6.38  1.96  28.9 1.95315  websiteOrder 38.85  6.38  6.38  3.01  41.86 3.010875  salesOrder 38.85  6.38  6.38  3.02  41.87 3.010875  websiteOrder 76.33  6.65  6.65  5.53  81.86 5.533925  salesOrder 76.33  6.65  6.65  5.54  81.87 5.533925  websiteOrder 134  6.72  6.72  9.72