I may be wrong, but I think the 805s have different engines to the 800s and 802s (I think they have the 810 engines), which would explain the different subclass there (yes, I know that the 158s have different engines within the same class, but TOPS is inconsistent).
I don’t really know why 807s are classified as such, I don’t know if they have backup diesel generators like the 801s, but if they do, then presumably the fact they weren’t procured under IEP would explain the classification (as stated by
@LNW-GW Joint); otherwise, I don’t see any reason as to why they aren’t classified as 803s (I remember hearing somewhere that they need some sort of weight in place of the engines, so they went for batteries).