i've been using Blackstone. fast and reliable. they recently caught my mistake. i sent in sample as 5w30 and they made notes about the viscosity being odd, that it showed more like a 5w20. in fact i did send in 5w20. i replied to the email they sent me with the report letting them know "thank you for catching that" and they will now update and resend me the report, etc. so, in this case they are actually aware of the #'s, etc.
UOA can be subjective. if you are debating pricing you can only debate it between UOA shops if they do the same tests via same testing standards, etc.
imho,use UOA to dial-in your oil brand/type/usage etc, then do UOA every other fill to keep an eye on any signs the motor may be churning up, etc. if you do $$ comparison including UOA you'll find the costs to be about equal annually if you do ~7500mi+ changes in synth, and you might save a few $$ using quality dino oil.
many posts here on bitog about UOA are discussions about the oil, but the main purpose of UOA is to detect problems with the motor, just like seeing your doctor for a annual check-up, etc.
