Danny, please don't take this in the wrong way, but in industrial production, there are always going to be variations. Perhaps nowadays the changes are better tracked, but variations will nonetheless occur. You generally hope that they occur to improve the product, but generally they occur by error or as a manner to reduce costs. I therefore generally hope for things to be more standard as most "exceptions" end up being lesser...
The second thing is that Velobase is far from being infallible. If I had the time and inclination, I am certain that I could come up with many glitches, omissions and errors. It is however a fantastic resource and everybody should be super-thankful for its existence.