The context is not what it seems.
Correction here is only in bass. There is no need for spatial averaging if that is all you are doing. Yes, you have to worry about non-minimum-phase nulls but you can do that without any spatial measurements.
If you want to do correction in higher frequencies, then yes, you have to have a strategy for smoothing as slight changes in microphone location can make a big impact on measured results. Comb filtering for example is a big problem in higher frequencies which smoothing helps to resolve.
In bass frequencies, modal peaks can have resolution of less than one Hertz. Smoothing can produce incorrect results for filter programming for example.
As I noted, the problem with multipoint measurement is repeatability. You absolutely want to listen to experiment here. To the extent you can't repeat a multi-point measurement because you can't identically move a microphone to different spot in 3-D space, then I rather use single point measurements.
Now, if you have multiple seating locations, then that is an entirely different game and you do need to measure more than one seat to build a model of what to correct. Even here, spreading the measurements across multiple seats equally can reduce the preference in the outcome. From Sean and crew's own AES paper:
The Subjective and Objective Evaluation of Room Correction Products
Sean E. Olive1, John Jackson2, Allan Devantier3, David Hunt4 and Sean M. Hess5
View attachment 152409
Any kind of averaging gives you suboptimal results for the corner cases. Here, if you all you care about is a single location, then averaging just reduces the resolution there, not increase it.
Bottom line: keep bass optimization separate from rest of the frequency response. They are completely different animals as Sean and Dr. Toole would tell you.