Originally Posted by
Beaulieu
I wouldn't read much into it - the BA number is what you need for doing stuff with BA I'd have thought. The different reference numbers could well be just based on your booking being made in something other than Amadeus (BA's GDS) and so it got copied and a shadow PNR made for BA's purposes.
It's likely that UB's booking service uses Saabre or Apollo or some other GDS.