Ah ok, you should have explained that in your original post
I remember I had a similar issue with WCF once, not with that particular attribute, but with a similar one that limited the amount of items that could be in the "object graph", and I followed all of the tutorials but the program ignored my changes. It turned out that it was not actually using the config file at all, because when I removed all of my service endpoints from the config file the program still ran as normal, where as it should have told me that no endpoints were configured. Can you try doing the same thing just to confirm whether or not your app is actually looking at the config file at all - comment out all of the service endpoints (including the MEX endpoint if you have one) and then try and start your service host and see what happens...