Dear Bruce,
The coupon system that awocoupon uses handles discounts quite differently from the coupon system built into VirtueMart. You are right, both use the same input field (so in the rules you can check whether a coupon code was given, but the exact discounts are not available in the rules), but the coupond discounts are handled completely different.
If all you need to check is whether a coupon was given at all, then you can still check the Coupon variable in your rule:
Name=No coupon; coupon==''; Shipping=123456
This is exactly what you mean with your COUPON==BLANK request.
However, you cannot check for the exact coupon discount or which coupon (as awocoupon stores a lot more than just the coupon code in the Coupon variable).
Best regards,
Reinhold