Eh, either way, no way he could he be less than 4200 at that point, will or no will Goku would bitchslap him into a coma with a PL gap that high, especially in early DBZ where Power levels were basically expos to who'd win
Sure, but it does create a bit of a question mark.
Personally, it's my headcanon is that the Promotion Based system is simply inefficient/ineffective due to corruption, or despite it's existence is simply not utilized at all by Saiyan society (because this was very clearly retroactively added in by Toriyama). Vegeta considered Goku Low Class despite being at 8000, and even when he proved himself near to the Prince in power. He considered Raditz Low Class, but Raditz was at a 1,500. Stronger than most in the Force, and we know "Super Elites/Elites" are the Vegeta bloodline at 10,000 (or higher). Nappa is Mid-Class, but he's at 4000, so he should either be Low-Mid Class and thus not be as rated as highly, or characters like Raditz should be rated higher. Especially since he's
officially Mid-Class, according to Toriyama (yet in story they act as if he's claiming that as a lie). King Vegeta considered Paragus Low Class, but Paragus was at 4,200 and was a
Colonel. Meaning he should be rated MUCH higher, and have a rank comparable to
Nappa's. Hell, this seems to be the case in Toei. Turles had a PL of near 30K and was considered Low Class. Z Bardock was near King Vegeta (at 10K) but he never got promoted. Tarble was considered humilating in power level and fighting Spirit, sent away, but he was able to fend off Abo and Kabo, who were of equal rank to
Captain Ginyu. There's no rhyme or reason to the ratings, really.