Average summary column NAN when all values set to 0 or blank cell. Instead of NAN shouldn’t this be 0 or blank and not ERROR. Also if you enter 1 in one average cell and set the rest to zero. the average comes out at 1 and not 0.2 for example.
in the example below modify the E column to all zeros to get NAN. Then change one cell in E to 1 or 23 etc to get the wrong average result. In fact any blank or zero column is ignored in the average calculation
ie
10 10 10 10 0
should be 8 as 5 cells but results at 10