UA sets aerobic threshold by lactate at 2mmol or 1mmol above baseline. So, in your case ~147 bpm.
> We use the widely accepted blood lactate concentration of 2mMol/L to define AeT. However, some literature suggests a concentration of as high as 2.5mMol/L, and one method defines AeT as the point where lactate rises 1mMol/L above the lowest reading obtained during the warm-up or while the athlete is resting. Just be consistent with the measurement and protocol you use. 
Not an expert, but from what I’ve read, there are many definitions of aerobic threshold. The first point of deflection in lactate is another, as suggested by your lab (~132 bpm at sample 3). In this case, they may also be referring to aerobic threshold as the floor of your Zone 2 (in a 5 zone model), which would be equivalent to Tempo in their training zones? Whichever, it’s an interesting mark in physiological change – lactate is increasing, suggesting fast twitch muscle fibers coming into play.