I remember a dept. order a few years ago reclassifying the High Pressure Engines as 3rd Stage Engines, & 25 additional Engines were reclassified as High Pressure Engines. Here is the list,
Division 1 - 1, 4, 7, 9, 24
Division 3 - 21, 22, 23, 40, 76
Division 6 - None
Division 7 - 66, 67, 72...