In the sprawling litigation over the 2010 Gulf of Mexico oil spill, BP won a potentially important round in the federal appeals court in New Orleans. Now Americans will see whether the British oil giant's victory pays off in the federal trial court -- and it just might backfire. The US Court of Appeals for the Fifth Circuit in New Orleans yesterday blocked certain spill-settlement payments for private business claims that BP had alleged were exaggerated or "fictitious." The ruling amounted to a rebuke of US District Judge Carl Barbier, who had appointed and vigorously defended the claims administrator. So far, BP has paid out some $26 billion in cleanup costs and claims related to the spill and rig explosion, which killed 11 men and sullied much of the gulf region.