I'll be the first to say that the OTS for the N63TU specifically is garbage. OTS in general aren't great, but for the N63TU they have a history of being terrible. I also know of a few people that have had blown N63s seemingly due to their tune. I'm not sure of the most recent revisions(because I went custom asap after learning about the flaws of their OTS), but earlier versions of the tune targeted boost levels above what the factory tmap can read. This of course caused unmetered boost, extremely high IATs, detonation etc.
I have PAGES of conversation history from Halim, Dzenan etc going back and forth about their tune and what they need to fix on both my car and another N63TU owner that I met when I started digging. The current e30 OTS was even developed on my car. I of course wont be posting them here so don't bother asking.
I also wouldn't be all that surprised if many people who have had issues have been blocked/banned. BM3 has a history of blocking/kicking/banning people that disagree with them or call them out for wrong doing. I personally have been banned from their IG just for asking about questionable dyno numbers. I know many others across other platforms (facebook etc) that have been kicked for similar scenarios. Even the most reputable/relevant tuners for N63 have been kicked from the BM3 Facebook group.
I wouldn't be surprised if I get banned from this forum (as I am sure they are a sponsor) after this post lol. Someone screen cap this so if this post goes missing you have proof 
With all that being said, scored cylinder walls is an awkward conclusion if the tune was the culprit. Cracked rings, bent rods, spun bearings would all make sense. Scored cylinder walls, not so much. Not that it isn't possible. If injector dwell time was through the roof or something of that nature, and the cylinder walls were getting washed constantly then maybe. Its more likely the scoring was caused from the rings getting blown out and that would also be why there was no compression. Did they look at the pistons/rings at all?