The headline of a Post editorial of Oct. 14, "Making Child Support Fair," was totally wrong. The rules promulgated for the District by Judge Ricardo Urbino may make determination of a support amount easy, but the resulting figure is almost certainly going to be perceived by everyone to be completely unrelated to the actual costs of raising children. The premise that Judge Urbino used as the basis for his formula is demonstrably false. Children's needs do not rise as the income of their parents increases.

As a member of the Virginia Governor's Commission on Child Support in 1985, I examined a similar proposal for Virginia. It readily became clear that there was no credible research to support the conclusion that parents spend a fixed proportion of their income on their children. Children do not eat twice as much food when their parents' income doubles, nor do they normally buy twice as much clothing merely because their parents are earning more money. Yet Judge Urbino is asking noncustodial parents to accept such nonsense.

Sadly, such punitive support awards as proposed by Judge Urbino will make custody battles more bitter and vicious than ever before, since the "winner" stands truly to destroy the "loser." Judge Urbino has created a positive disincentive to cooperative shared parenting arrangements in which little or no money normally changes hands, and in which children enjoy maximum contact with both parents.

Under the judge's plan there is serious money to be made by becoming the sole custodian. The "loser" loses not only his children, whom he may never see again, particularly if the "winner" decides to increase the punishment by moving to a distant state. And the "loser" will find that after federal and state income taxes, FICA and this so-called "child support" he will be taking home less than 50 percent of his gross income. If there is more than one child involved, the amount will be much less.

The inevitable result of the rigorous application of this punitive plan will be for more noncustodians to go on the cash economy, where they will be able to keep some of the fruits of their labor. Or they may change their identity and start a new life elsewhere. In either event, the children will be the big losers as they will have only one parent when they are entitled to two, and there will be less money available for their support.

For the sake of our children, the D.C. Council must insist on support standards that are based solely on the actual costs of raising children. These standards should give equal monetary credit to each parent for the time each spends with the children in order to encourage parenting time by both parents. The support standards must be fair and must be perceived as fair. Judge Urbino's standards fail badly on both counts and must be rejected. CARL FRIEDMAN Arlington