Quotron Systems, Los Angeles, said it signed a multimillion-dollar agreement with San Francisco-based Charles Schwab & Co. to provide financial information and other support services to Schwab's account executives and traders throughout the company's 92-office network . . . Los Angeles-based Beneficial Standard reported that it had reached a definitive agreement to sell its Glacier National Life Assurance unit in Canada to Service Corp. International of Houston . . . Miami-based Eastern Airlines said it flew a record 3.02 billion revenue passenger miles in March, a 14.1% increase over the 2.64 billion it flew in the like 1984 month . . . A senior Transportation Department official overturned a lower-level decision and tentatively chose Miami-based Eastern Airlines over World Airways, Oakland, to fly a new route between Miami and London, the department reported.