Ah.
Yea, FLL OC Mode to enable high OC frequency is only supported from ucode 0x12. So not supported in the 0x9 ucode you're using for non-K OC. That's probably why setting it in BIOS doesn't do anything.
As far as I know, CPU-Z has server-side checks for FLL and microcode to ensure the proper configuration is used for validations (to weed out any of those false high frequencies). My guess is that your validation got blocked because it lacks the proper ucode/FLL OC configuration (not because someone manually intervened).