Patricia Smiley transcends a conventional plot about insurance fraud and a missing business proposal by introducing Tucker Sinclair, an irreverent 30-year-old financial consultant. Recently divorced, she's reluctantly sharing quarters with her eccentric actress mom (who calls herself Pookie) and in danger of losing her Malibu beach house to an aunt contesting Tucker's inheritance. Then a prickly client turns up dead. So Tucker plays detective to clear her name of charges of bilking investors and possibly murder: ''I felt as if I needed Dr. Watson and a couple of Valium.'' False Profits is often predictable, but its feisty heroine boosts the bottom line.