Hi srturner47, appreciate your work! It's a great mod.

I'm using version 1.5.3, but still have problems on the calculation of the shipping tax and group discount.

The shipping tax problem has been mentioned in some previous posts, but I didn't find the fix to that. The shipping fee is hard coded in edit_orders.php
Code:
  $AddShippingTax = "0.0"; // e.g. shipping tax of 17.5% is "17.5"
Since the shipping tax rate varies according to the shipping address, the shipping tax rate should be retrieved from the database when needed.

The discount problem is also there. When edit an order with group discount in order_total, the mod will add the discount to the total instead of subtracting it from the total. This seems to be easy to get fixed.

BTW, I have a problem making Edit Orders mod and SplitTaxLines mod compatible. SplitTaxLines separates taxes into several lines and saves them by several rows in table order_total with same type 'ot_tax'. When I edit orders, the sum of taxe rates will be applied to each line of tax. As a result, the total tax may be doubled or tripled or more according to the number of tax lines.

Please help me out. Thanks!