"Harlan Grove" wrote:
....
These results arise from the INDEX calls, which return arrays of
arrays. Excel copes with this return type the same way it does with
arrays of range references (e.g., INDEX(A1:D5,0,{1,2})) - by using
implicit indexing when entered into multiple cell ranges.

....

Enter your last formula into a 1x4 cell range and you'll get the same
result as your first formula above. Why? Because Excel applies the
outer MAX function to each, er, subarray returned by its argument, and
each of those is a degenerate array with a single value.

"Curiouser and curiouser!" Apparently cell ranges are required to elicit
this behavior. I tried embedding an INDEX() call within the outer MAX() to
obtain the value from a different column, but that only gives #REF!

I know what I believe, but do you believe anyone on the Excel
development team could explain these semantics? They've certainly
never bothered to provide any documentation about them.

I won't hold my breath.

Jerry