I have an early 2012 model which had a screaming bevel box. We endured for almost three years and then got a second box . Unfortunately this also was a screamer.
During the last year I have removed the bevel box ( an easy job ) for numerous reasons. I decided to have a go to improve the situation and gave to a diff specialist. He put in new ( better?) bearings, changed crush collar to a shim arrangement adjusted backlash etc. Result was basically no change except for when the screaming was at a peak.
Not to be daunted I tried again with a gear manufacturer. They had quick look and could see the wear was indeed at an extreme (can't recall if heel or toe). This was adjusted to be a more central pattern. Net effect was similar to above. Another change of when it was noisy, but little reduction overall. Possibly less screaming but more general gear nose.
Hence I was very interested to read your comments on lapping effectivity. I had tried to find somebody to do this before but unsuccessfully.
I would be keen to find out if sending my box to 3 Star Classics was a possibility. Hell would take it over in plane myself given the low cost of fares from NZ to Brisbane !!! Given they have done a couple already, they could be considered experts ! With a better chance of success.
This has rekindled my interest in perusing the lapping. The weather is utter crap here at present so a couple of weeks off the road is a small price for the chance of a quieter future