I am not sure if it's anything to do with nationality. I140 can be very crucial for indians too, in case if you are running out of 6th years and about to file an h1b extension. In case you have an I140 approved and your numbers not current, you can extend your h1b for 3 years.
I read somewhere on trackitt forums that USCIS handling I140 cases little faster for those about to be running out 6th years, which fits to my case.
Also I think that if there is something important component missing from your application package, USCIS tends to send RFEs earlier. Will see when I receive the RFEs.