GSA Goods and Services Tax Known Issues since Base Release
 
IO12506 If GST is used, and Tax Table 3 or 4 is in use, Store Coupons do
        not reduce the tax from Tax Table 3 or 4 even if STORE COUPON
        TAX REDUCTION configuration for Tax Table 3 or 4 is set to Y.
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  1 APARs listed. 
Last update Mar  2 2015