Just want to report on a bug as Im sure of it.
Working with FedEx Web Services on several errors
Most error's would send you an email stating
"Customers have experienced issues with receiving rates from the FedEx shipping method. Please make sure that is configured properly and that the shipping rate calculation is correct"
After debugging with them, and of course they see the errors on their side all concluded to page 702 FedEx Developer Book.
Non the less the fix is simple, and everything started to work, with no emails bombarded by our servers.
Line 297 'RateRequestTypes' => 'PREFERRED',
Changed to 'RateRequestTypes' => 'NONE',
This still would push out your preferred rates and not published.
If you want both rates to show, change 'LIST'
Hope this helps someone, as I was pulling my hair out.