The expert advice on buying automobile insurance in the Policy Matters column {Style Plus, Jan. 7} boils down to a few well-worn platitudes: shop around, ask for discounts, avoid accidents and don't submit claims.

The real message, however, is that buying car insurance is a state-regulated ''game'' run by insurance companies in which car owners are either smart players or dumb losers.

What experts don't admit is that the winners' discounts -- a tie-in purchase of a homeowner's policy, for example -- must be subsidized by consumers too poor or unsophisticated to play the game. The discount game conceals the real business of providing large subsidies for some drivers at the expense of others.

Without the discount mystique, consumers would see that the real winners in the auto insurance game are those who drive more than average. An $800 premium for a particular rating class may look big, but it costs less than 4 cents a mile for cars in that class driven more than 20,000 miles a year. The same premium costs more than 16 cents a mile for cars driven less than 5,000 miles, minus a penny or two for the low-mileage discounts offered by some companies. With the blessing of insurance commissioners and experts, companies charge owners of the lower-mileage cars four years of premiums for the same amount of on-the-road insurance protection that owners of the higher-mileage cars get with one year's premium.

Accident probability and insurers' costs increase with every mile driven. Without experts to mislead them, ''losers'' would demand conversion of class rates from dollars per year to cents per mile. Premiums would be objectively calculated from readings of sealed odometers, as is now done for some commercial vehicles.

Until the truth is told about the per-mile alternative, however, upscale consumers who can afford gasoline and the $25 price of Ralph Nader's ''Winning the Insurance Game,'' which is recommended in the column, can continue to win with token discounts and the high-mileage subsidies they conceal. TWISS BUTLER Staff Analyst, Insurance Project National Organization for Women Washington