The original Tuxedo 15991 was not given a new Dulux code, I believe it is straight black tinter, it was always available pre mixed there was no formula listed. Tuxedo Mk2 is as you have typed.

Midnight Black has the old Dulux code of 31466 and was a 78/80 GMH Commercial colour.

All blacks are listed under the new codes of 1Kxxx
Warrigal is 1K002
Ebony Black is 1K004 (this is an 85 Isuzu colour)
1K003 is not listed in any material I have but may be either Tuxedo or Midnight Black try your paint people with this code

I just noticed you had 5131 listed, the Black tinter has a code of 5431 might want to check if your 1 should be a 4............ Blocker where is the grasping at straw emoticon??