If things weren't so complicated they would be simple. Take Personnel Program Codes. Three codes, simple. Tier 1, Tier 2 and Academic. Tier 1 and Tier 2 employees are staff.
Academic employees are, well, academic.
The Academic code is straightforward, so let's concentrate on the other two. Tier 1 includes BOTH non-represented and represented staff employees. Tier 2 has two groups, Managers and Sr. All Tier 2 employees are non-represented. The Personnel Program Code is derived by the PPS system.