Tax is not calculating correct when discount coupon is used.

Example using 10% discount below:

##################################################__

Sub-Total: $4.27
##################################################__

Discount Coupon: XXXX : -$0.43

Canada Post: $7.49

5% HST: $0.21

13% HST on Shipping: $0.96

##################################################__

Total: $12.49



Show Split Tax Lines: true


Discount Coupon setting in admin:

Discount Coupon

This module is installed
true

Sort Order
280

Include Shipping
false

Include Tax
false

Re-calculate Tax
Standard

Tax Class
--none--


Zen-Cart Version Below:

Zen Cart 1.3.9d
Database Patch Level: 1.3.9c


Any insight will be great.
####################__
Wendy