Listing Package versus User Credit Balance

Hi Guys, can you please confirm if this happens also to you ( using Classified themes 8.1)? I have my listing package set for example at $20 ( for 1 enhanced listing). If i give a user a $40 credit ( from the admin menu area), he can use that credit to list 1 ad but as soon as his credit is down to $20, he can not post a paid listing anymore. This should not be the case right since his credit is still equal to the listing package cost? Appreciate any feedback.