Can I argue H1's valid date with USCIS?

A friend of mune applied for 3 years H1b by employer, but USCIS gave 2.5 years.for example, 12/01/2006 valid through 05/10/2009, but the expectation should be 12/01/2006 through 11/30/2009. Is that possible to give the full 3 year after argument?Thanks.