I know!
I thought I'd do the same one night, only in reverse. I've been using 3 filters since forever, and thought I'd go for a ruler flat response just to see what it'd sound like. Well, after much fiddling and measuring and remeasuring and re-fiddling I ended up with 9 filters. Still a little ripple, but not too bad, I though. Sounded okay, but not spectacular. Then I brought up my original curve, and overlaid the new curve. They were almost identical. the small ripples were in different places and such, but the overall curve was very similar. And the 3-filter setup sounded better too. Maybe just to my ears, but still. Placebo-effect is still effect..
Needless to say I kept the 3-filter setup.