I set the coupon usage number but user can still using it without login

Hi,

I just bought the AwoCoupon extension.
Our website was using AwoCoupon Free version before this purchase, and everything works fine.

After I updated to Pro version. It become no log-in required to using coupon code (which I set Number of Uses to 1).

Case 1:
Joomla! 2.5.24
VirtueMart 2.6.10
RuposTel One Page Checkout (2.0.266.271014)

Case 2:
Joomla! 2.5.17
VirtueMart 2.0.26d (and pasted the code in coupon.php)
RuposTel One Page Checkout (2.0.230.240214)

Two case, same problem.
In case 2, the only change is update AwoCoupon to Pro version.

How can I fix this?
I'd appreciate your help. :)

Hello,

In the pro version, the number of users per customer does not require log in. I works on the order email and checks the restriction there.