Is this still the code used to generate the price?
http://pastebin.com/u0PSarFs

I very much doubt it is.

Bitfloor and tradehill don't return prices anymore.
The mtgox webservice connection does not work for me on two different systems and the price would be much higher if included.
Bitstamp bans me after a while.

So that only leaves coinbase working 100% and bitstamp sometimes.

Using coinbase/bitstamp and adding btce seems to match your prices best. If I add mtgox the price gets much higher.

Can we get the updated code please?