Infinity Broadcasting Corp., the company that employs radio badmouth Howard Stern, could face fines up to $ 900,000 for broadcasting smutty shows on three stations last year, Federal Communications Commission member James Quello said yesterday.But the five FCC commissioners continued to be torn over whether to punish N.Y.-based Infinity for indecency or to refer the case to an outside administrative law judge, commissioner Quello said. Late last month, Quello said the FCC was considering a fine of up to $ 315, 000 against Infinity, which would be a record if levied. Yesterday, however, he said FCC lawyers had determined that the fine could go as high as $ 900,000. They arrived at the total because three Infinity stations ran the disputed shows for 12 days. The maximum fine for broadcasting indecent material is $ 25,000 per day, Quello said.