Work Days Outside of State (NY / NJ)

Hi.  I am filling taxes our for my son.  He lives in NJ and works in NY.  He is a college professor and is only on campus in NY 3 days/week.  I am confused about the allocation of days.   He started ~Sept1, 2020 so let's assume 120 days.    Let's assume 32 weekend days and 6 holidays leaving 82 (54 on campus and 28 off campus outside of NY)  When I get to the screen ... workdays outside of NY there are 2 boxes.  One is "outside of NY".  and the other is "worked outside of NY at home".   Do I fill in 28 in the first box and 0 in the second box?  He was doing research for papers and potentially doing grades etc at home, but was not in NY.   (If I fill in 28 & 28 it basically doesn't allocate any of the income outside of NY and basically acts as if I never made an entry).  

Thanks in advance.  I've never done a return like this so appreciate the help.

Brian