Search Engine Bot followup - True Searchbot ROI

I did a post a while back here in which I talk about how much traffic search engines are sending me vs how much they are indexing me. It was a fun and interesting stat (to me) but as people commented it really doesn't meant that much. Going from the last 5 months data (Jan-April) I took it a bit further I calculated all the bandwidth each bot is using (using webalizer) vs how much organic traffic I am receiving that converts to a sale (using Google analytics). So I averaged this to a daily breakdown. (keep in mind that Google is using gzip and caches now so it should actually perform better over the next 6 months). This site has no contextual ads so only completed shopping carts are conversions. Now we have a true cost analysis- This is purely organic stats and a true ROI for spiders vs conversion over a 153 day period broken down per day. Ask COSTS me $7.90 per day. MSN Gives me $29.85 per day. Yahoo Gives me $124.23 per day. Google Gives me $227.44 per day. Now I like ask.com but cmon... improve your fricking bot already. You are chewing the most bandwidth from me yet you give craptastic returns.