LAX success: MI only on BP, full name on ID field
Told the Van Nuys FlyAway driver "United Premier" which I wasn't (yet). Got off at T6 and headed to the roped "off" PreCheck line. Ducked and crossed. Non-TSA staffed asked whether I was PreCheck. Still to this point I couldn't be sure I really belonged, but less than half a minute later, THREE BEEPS!
BP only had LAST/FIRSTMMR. My online UA ID field had my full middle name. I believe it was without the hyphen, but it still worked.
Tomorrow's return from ATL will be AA, which doesn't officially have it yet. I'll go to the south PreCheck line and try. Report will be on AA's thread.