If you look carefully, there is no software support listed by your eBay seller (Mastach) for the '94 and '95 Bonnevilles (and other GM compatibles). The software may or may not support them.
These hybrid OBD Bonnevilles are OBDI protocol, but yield expanded OBDII codes. So they're different from everyone else.
I have sent Mastach a message (Thursday) asking him about this, but I have not gotten a reply back yet. I will post it if I do.
Roadrunner1, since you have a '94 Bonneville, I would advise you not to try Mastach'* kit, certainly not at this time. You would probably have to evaluate additional software, and also have to pick up the appropriate J1962 male plug (not included that I can see) that has to be adapted to Mastach'* kit.
For those '94-'95 owners with a laptop, a serial port, and a high threshold of pain, if you try it, let us know how you do. I'm always interested in this topic.