I know a few farms that breeds true
XB and BBXB or Bukit Merah fishes
Check their fb.
https://www.facebook.com/AsianArowanas - this breeder specializes in true blue base crossbacks as evident in their old website (not available now) unfortunately they don't ship to the PH. I been eyeing on this breeder for YEARS yet the farms that penetrated our market mostly IPOH,OS,AP Trading, SIANLON, Sanwa, Pt global, One Red x RDC, Lucky Indo Aquatic, DARISTO, BrotheRed, BINTONG, 88 red , KINSTAR and Longxin(rare now).
https://www.facebook.com/imperialarowanafarm - This one have their own lineage of Bluebase XB
Panda - never saw this farm anymore but they really have premium fishes way back
Merlion - This farm focuses on development and crosses
Going back to your question I agree with Stratos, It all goes on the line of breeding. Premium fish commands high prices evident to the depth of color and pearlies too.
Note that some SHBRTG even become crossbacks since farmers use to breed RTG to XB to get a much more higher shine yet its hard to find a pure bred RTG now.
So the XB sold here might be just SHBRTG that is higher in quality.
Also note there are no XB that has spoonhead, since spoonhead are only found on REDS
Takeaway is you pay premium with the knowledge that your fish came from a line that breeds true.