The only thing I can think of is if this tool is from an earlier VU where the TIRs were different for each level. This tool could of been 3000+ in stages 1-8 and tier 9 was 128/4000. The owner could of tiered it up to 8.99, then the VU happened, which reset all TIRs to the next highest TIR that hasn’t been unlocked yet, 128 in this stage. It was then decayed to T10 under the new system.
Though I’m not sure even when starting from a relatively high TT that achieving T10 would even be possible.