I wondered whether any of the wise denizens of DC might be able to offer some advice.
Not much to suggest other than to say S.M.A.R.T. isn't a tool that gets relied on for absolute accuracy since it's less a real-time monitor and more a "heads-up" warning system that may
help you predict immanent disk failure or help diagnose oddball conditions that suggest you're heading towards one.
In practice, I've generally found SMART is not all that useful on the user level. Because by the time the OS becomes concerned enough to forward a SMART-based alert to the user, it's pretty much too late anyway. I'm guessing the drive manufacturers probably make better use it for QC purposes and as a 'failure validation' tool when customers make warranty claims.
I'm not sure what your goal is by recalibrating the temperature sensor. If it's for intellectual curiosity or a learning experience, that's fine. If it's to get longer drive life, you might want to consider that some recent studies seem to have concluded thermal fatigue and high operating temperatures are nowhere near as much a contributing factor to drive failure
as we once suspected. The bulk of the failures seem to occur for mechanical and electrical reasons unrelated to heat.
The excess heat generated by a hot drive can however potentially damage surrounding components, so it's probably not correct to simply dismiss hot running drives as "not a problem" in every circumstance.
I don't know if HDS is definitely "on" to an unaddressed problem - or if it's more something they're recommending simply because their product can
do it. You'll get a lot of that with some utilities out there. But I don't have sufficient experience with HDS to make a call ...and I've never once heard of anybody
manually recalibrating a drive's temperature sensor like that...sooo
I guess I'll have to wait to hear how you made out if you decide to go ahead.