Well, I was going to take a screenshot to just show you, but I guess since I
cannot upload it here, I'll try and explain it to you. You'll have to bear
with me, I'm not an Excel-savant, much of what I know how to do with the
program is trail'n'error and finding instructions on the web...

Here's how I set up the format I have working...

1/ Click the cell (L3), click on Conditional Formatting, and click New Rule.
2/ Rule Type: Format all cells based on their value.
3/ Format Style: Icon Sets (3 Arrows (Colored), Reverse Order Icon)
4/ ...when value is "" "=$M$3" "Number"
5/ ...when <= Formula and "=" "=$M$3" "Number"

And then I hit okay, and it works. The value in M3 is a number calculated by
a formula within a cell.

Thanks,

Matt