You know you're going good when a bookmaker tries to change the rules before the game is half over.

Like last week, when the time came to make a small commitment on San Diego against the Saints in New Orleans. Nothing serious, just a touch in order to keep in touch with the agony and the ecstasy of Sunday's point spread.

"What do you have it?" I asked Fidgety Fred, the neighborhood's friendly football numbers man.

"I got it even," Fred replied.

"Fine," I said, "I'll take the Chargers for the usual."

"O.K.," Fred said. "but you got to give a point."

"I got to give a what! I shrieked, refusing to believe what I was sure I had heard.

"You got to give a point," Fred repeated.

"So what if I wanted the Saints, what would I have to do?" I asked Fred, figuring this was one converstion that had no place to go but up, just like the spread.

"You eant the Saints, you got to give a point," Fred said.

Silence.

Then:

"And what do you have the game?"

"It's even," the bookie answered.

Never underestimate the importance of a point or a half-point. And don't permit any bookmaker to commit this kind of larceny. Walk away.

Betting with a bookmaker is not always beautiful, no matter how long and reliable the relationship has been. Tomorrow is always a new day. Bookies don't enjoy losing streaks any better than a bettor does. And they cannot always balance their action on a particular game.

There is a great misconception in the public mind as to how a bookmaker functions. If his book is balanced he couldn't care less which team wins. If he takes $1,000 on the Redskins and $1,000 on the Cowboys this SundayM he is in a can't-lose situation. The vigorish will net him a $100 profit on the $2,000 bet with him, inasmuch as all the money is wagered with the understanding that the bettor is risking $11 to win $10. No fee, or vigorish, is paid by the winners, only by the losers - and ties involving the spread result in nobody winning or losing,.

Many bookmakers insist on the player risking $6 to win $5 for any bet of less than $50.

"It's an inconvenience taking all the little stuff. It just adds up to too much paperwork, they will tell you.

Don't believe that for a second. The difference between the 11-for-10 and 6-for-5 (12-for-10) is tremendous over the course of a season. There are bettors in Las Vegas content to operate on a 53-47 margin. Playing with large volumes, they know 53 successful selections out of 100 over the 17-week schedule mean an income of $53,000, a loss of $47,000 plus $4,700 vigorish, or $51,700, thus a bottom line of $1,300 profit.

Pick 52 out of 100 games correctly and the same player is a loser, because 52-48 doesn't make it. You would win $52,000 but lose $48,000 plus $4,800 vigorish for a net of minus $800, plus all the time and nervous energy invested.

I feel sorry for bookmakers in the Washington area. They are under the gun from the Supercops. They have the fastidious Feds in their backyard. But that is no reason for anyone to start shaving the spread by making "even" games one point both ways. There ought to be a law against such shenanigans.

Horace Greeley had the right idea. Go West (or North or South). Playing on the home field is no advantage.

This is another light week I will stick with Dallas one more time, risking $250 while giving nine points and hoping, as a Kilmer fan, that Billy isn't devoured by Harvey Martin and his aggressive friends.

Kilmer is in for a long afternoon. I will also go with Pittsburg for %500 at home Monday night against Cincinnati if Terry Bradshaw plays. The spread will be fewer than seven points.

My other games of more than passing interest are Atlanta giving two (up from one) over Buffalo, Cleveland getting two at Houston, Denver getting 9 1/2 at Oakland, New Engalnd getting 1 1/2 (up from one) at San Diego, St. Louis getting four (down from 4 1/2) at Philadelphia and San Francisco even at the New York Giants. How can the Giants be favored over anyone?

Finally, there is Kansas CIty getting 13 from Baltimore, Chicago getting seven at Minnesota, Detroit giving Green Bay seven, Los Angeles giving New Orleans 12. Miami giving the New YOrk Jets seven and in the Futility Bowl, Tampa Bay getting three from Seattle.