In a summarized saved search, I have a formula numeric field with AVERAGE summary type and where the formula is field A + field B + field C. It just sums the 3 values instead of averaging them. Why is that?

It sounds like it's pulling average sums for the three fields then adding them?

Yeah. I was able to get the average in a messy way where summary type is SUM and the formula is (A+B+C)/3. Now I'm confused how the AVERAGE works. Looks like it averages each data field?

I agree I think the average is per field, and I agree I'm not sure why that would work in quite that way haha.

The search adds the three fields together on every detail line of the saved search, then averages all of those detail lines into a summary line. But the value of that field on each detail line is the same, so you're just averaging identical values

Try to put SUM(field x + field y + field z) in your formula