Well, it would seem that there where some updates to our product provider which made our store inopperable; I went ahead and adjusted some code and got it all working again.

I have no idea how long this hasn't been functioning properly, but I see some posts about it at our shopping cart provider as far back as april.

I went ahead and tested several orders and can confirm that it is now working properly.

I'd like to thank VIR3NT for notifying me of this issue.