For the first time, the Houston school district expects that it will have to pay several million dollars to the state of Texas under the so-called Robin Hood funding system. The oddity involving the state's largest district is prompting renewed calls for changes to the state's' complex school funding laws, which require property-wealthy districts to share money with poorer ones. The district projects that it will owe $3.7 million to the state next year. That would be only a sliver of the district's $1.5 billion budget, but many educators contend the funding system is flawed when a big-city district that serves mostly low-income children is forced to give up money.