When I put the group discount before the coupon discount, the line items add up correctly, but the tax is 2 cents too low and then the total is 3 cents too low. Again, this only happens when editing an order. The totals are calculating correctly through checkout.

Sub-Total: CDN $58.50
Account Holder Discount - 3%: -CDN $1.76
Discount Coupon: -CDN $10.00
Shipping: $10.98
13% Tax (ON): CDN $7.48
Total: CDN $65.20

Should be:

$58.50
$(1.76)
$(10.00)
$10.98
$7.50
$65.23