This issue relates to i21 Help Desk ticket: HDTN-376230 - Tax Report Calculating Incorrectly
The Tax Grid is not reporting correct information. 

Non-Taxable sales for Customer out to be 47 Million dollars but should be closer to 11 Million Dollars. I found below issues

 Issue #1

Tax groups for some tax codes/invoices don't show up in tax report even though they are present in the invoice. We have blanks for tax groups in reports

Issue #2

Incorrect Value on Grid vs Invoice

See  SI-12179 for example

Invoice shows Line Amount for CORN = 4010.11

Tax Report Grid shows Non-Taxable Sales = 224,566

 This seems to be incorrect calculation on grid

On invoice 

4.70 is the BU Price.  

4.70 * 0.017857142857 = .0839285714279 per LBS

non taxable = 47780*.0839285714279 = 4010.11

On Grid

47780*4.7 = 224566 (which is incorrect as we can't use Lb weight and per bushel price)

Issue#3
Split for Non-Taxable Sales (FN) is not correct

See invoice SI-10000

Split for second item across tax codes is incorrect - Non-Taxable Sales is 62.5 so split across two tax codes should be 31.25 or they should add to Non-Taxable Sales

Steps:

1. Create and Post Invoice
   1. Add an item
      1. make sure all the Tax Codes is NOT Tax Exempt
      2. With Tax Group
   2. Add another item with multiple Tax Codes
      1. make sure one of the Tax Code is Tax Exempt
      2. With Tax Group
   3. Add another item
      1. make sure all the Tax Codes is Tax Exempt
      2. With Tax Group
   4. Add another item
      1. make sure all the Tax Codes is NOT Tax Exempt
      2. make sure the computed Tax Amount is less than 0.004. 
      3. With Tax Group
   5. Add another item
      1. make sure all the UOM and Price UOM is not the same
      2. With Tax Group
   6. Add another item
      1. Without Tax Group
2. Open the Tax Grid Report

Acceptance:

1. Tax groups should be shown on the reports when present in the invoice
2. Invoice detail & Tax Grid should show same value
3. Taxable (FN), Non-Taxable (FN) should be the functional conversion of the Taxable, Non-Taxable respectively
4. Add  Exemption No and Exemption Reason
   1. From the Customer > Customer Tab > Taxing Tab
   2. Show after Account Status Code column
5. Add Override Tax Group
   1. From invoice screen > invoice detail > Override Tax Group column.
   2. Show after Taxes Added to Cost column
6. Add Tax Exempt Adjusted
   1. From invoice screen > invoice detail > Item Taxes screen > Tax Exempt and Adjusted columns.
   2. Show after the Taxes Added to Cost column
7. Add a new column called Taxable Sales (Split by Tax Code), Taxable Sales (FN) (Split by Tax Code), Non-Taxable Sales (Split by Tax Code), Non-Taxable Sales (FN) (Split by Tax Code)
   1. this will be the new Split column
   2. Ratio and proportion to the value of the Line Item Amount
   3. Show Taxable Sales (Split by Tax Code), and Non-Taxable Sales (Split by Tax Code) after the Tax Exempt column
   4. Show Taxable Sales (FN) (Split by Tax Code) and Non-Taxable Sales (FN) (Split by Tax Code) after the Tax Exempt(FN) column
8. For classifying sales as taxable/non-taxable
   1. Taxable Sales
      1. If tax code is not exempted (based on Tax Exempt / Tax Exempt Adjusted columns), show invoice detail total.
      2. If tax code is exempted (based on Tax Exempt / Tax Exempt Adjusted columns) and adjusted tax value is non-zero, show invoice detail total.
      3. Any scenario that do not fall on the aforementioned criteria, show zero.
   2. Non-Taxable Sales
      1. If tax code is exempted (based on Tax Exempt / Tax Exempt Adjusted columns), show invoice detail total.
      2. If tax code is not exempted (based on Tax Exempt / Tax Exempt Adjusted columns) and adjusted tax value is zero, show invoice detail total.
      3. Any scenario that do not fall on the aforementioned criteria, show zero.

https://inet.irelyserver.com/display/AR/Tax+Report+Grid