I really don't want to say how one should use the meter and arrive at the exposure he/she wants. I simply first show the OP how to calculate the average of several spot readings in the fashion that a meter with that function would do. I don't say it's a good or bad approach. I did make a comment that if you average a lot of readings then you come up with the same reading as if you use a wide angle averaging meter instead of a spot meter.
I was probably reading to quickly and to quick on my comment, no offense meant to you or Bill.
Mark Barendt, Beaverton, OR
"We do not see things the way they are. We see things the way we are." Ana´s Nin