Best Way to test Paid Keyword Urls?

The paid keyword campaigns are not working properly on our account and I am having difficulty testing them to isolate the problem.

The documentation says the leadsource is stored in the browser cookie, but even though I delete the cookie and clear the cache on the browser, NetSuite still seems to retain the first leadsource I test with. 

Also, if I access my webstore using a url containing a leadsource and then create a lead account,  the lead account is created in NetSuite with an entirely different leadsource I have not used previously.  Example, my url contains leadsource=111 (this is visible in the address line) and my lead account gets created in NetSuite with leadsource=264.  Yet the unique visitors field is incremented for leadsource 111.