Texas GOP - Spending More To Do less

The Texas legislature has just authorized payment of $4.5 billion in Medicaid (which they left out of the original 2012-2013 budget to balance the books in 2011). That means the state is currently paying $4.5 billion every two years for the current (and inadequate) Medicaid program it has -- or about $22.5 billion over a decade. But if they expanded the Medicaid program under Obamacare, they could cover over a million more people and only pay $15 billion over the next decade -- a saving of about $7.5 billion. Does this make fiscal sense? What ever happened to the Republican idea that government should be fiscally-responsible and not spend more money that is necessary? Why would they want to spend more money to cover less people?