United Compensation for a Delayed Flight

A few weeks ago my United flight from Houston to Buenos Aires was delayed 13 hours. United automatically offered me 7,500 miles or $100 United credit as compensation, but I was able to increase that offer to 17,500 miles or $200 credit with a simple email.
The Delay
I was heading from the Chicago Seminars to my winter home in Buenos Aires. I booked the award for 30,000 United miles the week before departure using secret United award space.