Optimizing your extraction efficiency with thermal desorption is more than just temperature, imo.
I've worked in air sample analysis for years, and we used thermal desorption to flash heat our air samples into our gas chromatograph/mass spectrometer for analysis. We tested a variety of flow types and designs as part of our overall QA/QC protocol.
Temperature is just one controllable parameter when thermally desorbing (vapourizing). The flow design can be a critical controllable parameter, as well.
Most all vapourizers use a straight through, somewhat laminar flow that requires grinding of our herb, because this flow just doesn't penetrate very well, and needs more surface area exposed to work better. The air flow can be blocked if the bud is compressed too tightly.
The Herbalaire's design incorporated these 18 strategically placed "jets" (immediately before the cruc, or bowl) that create a more turbulent air flow. In effect, it is diffusing the air, just before the pack, resulting in the pack getting hit in all directions, simultaneously, as well creating a slight pressure drop at the same "jets" If anyone has flown through "turbulence", they know the feeling. (The pump also "pulses" it's air flow, which enhances the extraction, even more, imo).
This air flow design penetrates the load much more evenly and thoroughly, in fact, it is why there is no grinding required at all. Even dense, compressed, full nugs, will come out, fully and evenly cooked all the way through, light tan at low temps up to deep brown, almost black, at high temps, with never any green remaining. I know of no other vapourizer that can do this, at this time, and this thing is over 10 years old!
In addition, this air flow design penetrates and extracts so well, that I firmly believe that it works better if you compress the bud and try to block the air flow, giving it some resistance to push against. I tried to block the air flow intentionally by compressing the crap out of a load, but could not do it. Think of purging with butane to make BHO. The liquid bute is such a good extractor that you need to compress the bud tightly to give it some resistance, or more "residence time" in the bud, to optimize the yield.
This is why the HA can be so effective, even at 400F, as a max. It's their unique flow design, combined with its excellent heat retention and temperature precision. Quickest and most efficient extraction methodology, imo.