I’m just rereading this sentence and trying to figure out what else the 135 can be (or where it’s). In theory (based on LT1) it’s 11 bpm below my LT1. It’s a bpm rate at which I feel I’m doing hard work, I can talk, but it’s not like doing Z1 with kids 
If during the next test the decoupling will be very low, should I perhaps increase the target HR? (I read your posts Alternative method to find AeT and Optimal Zone2 HR Target - #6 by Sport_IT_Diederik + some external links).
During the test with mask, my LT2 was 171 and LT3 was 181 (and CFMax 184). Lately I’ve measured my HR at rest and it was around 50bpm, with some “lows” at 43/44/45.
Of course all those numbers are garbage after some months, but are still very fresh (test made on the 17th of January)