Are you referring to the Chevy Cash rebates? or the Tax rebates from the State?
if you refer to the Chevrolet rebates, they do offer a little extra to some states I've noticed. Probably trying to jump start sales there? they call them Select Market cash rebates. I dont know which states Chevrolet has that in, but Apparently Maryland is one of their 'select markets'
In short, Chevy is offering $5,500 nationwide, but there is an additional $1,000 offered in some markets.