xv18 and xc80 CFM question

I have a 3 ton unit and was looking at the default settings for the CFM for the fan (for AC its 400, for heat its 1380) which is the system default. The way I understand it both the blower and the AC are variable speed. ON the panel I can see the compressor spool up and down depending on need. How can i tell if the blower is doing the same? Also is 1380 a good CFM in the winter or is that the max and it will spool up from stage 1 to stage 2 ?

source https://hvac-talk.com/vbb/threads/2228751-xv18-and-xc80-CFM-question?goto=newpost