Score one for NBC.KRON-TV San Francisco dropped its plan to preempt NBC’s “Late Night With Conan O’Brien” in favor of MCA’s syndicated strip “Last Call.” NBC affiliate chief Bob Niles said he was pleased with KRON’s decision. “From time to time you have to reassess what this is all about,” he said. NBC had threatened the station’s future as an NBC affiliate if it delayed “Conan,” and no doubt hopes KRON’s decision will send a message to other affiliates that may have had similar plans. KRON-TV’s president and general manager Amy McCombs said in a statement that talks are under way with MCA about where to air “Last Call.” KRON’s reversal may also hurt syndicators who saw the station’s action as a move that could clear the way for new latenight strips such as “Last Call” and “The Newz.” Although this is a victory for NBC, the network has other unresolved issues with KRON, the foremost being the station’s preemptions of “Nightly News With Tom Brokaw” in favor of Oakland A’s baseball. KRON pays about $ 6 million in rights fees for baseball annually.