I have to admit that for now I am quite lost in the terminology like Format-A, Format-B, first order 1o, second order 2o, UHJ stereo, HOA > High Order Ambisonic
It has to do with how the recordings were made and the special microphones to capture "spherical" information on the incoming sound,, direct plane, reflections (rear), polar (up-down), etc. it is huge!
I also am trying these little free open source gems:
Ambisonic VST Plugin suite for Reaper
Latest Version v1.3.1, 17th May 2018
quite recent update
Interesting stuff and very knowledgeable!