Responding to complaints that moving companies deliberately give customers low estimates to get their business, the Interstate Commerce Commission yesterday proposed making movers' estimates binding.

The proposal would make the moving company's estimate the maximum amount that could be charged.If the weight of the load turned out to be less than estimated, the customer would pay less.

The rule was proposed after ICC investigations showed that about one in four moving bills is more than 10 percent higher than estimated.

Under present ICC rules, movers' estimates are not binding. The ICC said this often leads to "lowballing"-movers deliberately giving a low estimate to get the customer's business, then charging a higher price.

The ICC also is attacking another frequently criticized moving industry practice called "weight bumping." During the next three months, ICC inspectors and household goods to be sure customers are being charged only for what is moved.

By a 4 to 1 vote, the ICC yesterday issued its answer to the lowballing problem and asked for public comment.

The American Movers Conference promptly attacked the proposal as "unnecessary and discriminatory."

If adopted by the ICC, the new rules would apply only to interstate moves and not to all of those.

Moves from state to state within the Washington metropolitan area, or any other metropolitan vicinity, would not be covered. They are considered local hauling and are exempt from ICC regulations.

The ICC proposal would not require moving companies to give written estimates but would require any written estimates that are given to be binding.

Virtually all moving companies give estimates, and "we think the companies will continue to offer them," said ICC press officer Larry Lesser. "If I were moving, I certainly would insist on a written estimate."

The written estimates could be raised only if the customer asked more goods or asked for additional services and then the customer would be entitled to written notice of additional charges.

Moving companies would have to confirm their quoted rates three days before picking up the furniture.

The ICC said its proposal is meant "to deter any incentive to obtain a shipment by a purposeful misquotation of rates."

After studying the records of the nation's 20 largest moving companies last year, the ICC disclosed that 22.4 percent of the bills were at least 10 percent greater than the estimates. The big firms handled nearly half a million moves last year.

The moving industry contends that estimates are frequently wrong because of the estimating method established by the ICC. Estimates are made by figuring the volume the shipment will take up, and multiplying that by seven pounds per cubic foot to get the estimated weight.

Actual moving bills are issued after the goods are on the truck and weighed.

The binding estimate proposal was opposed by ICC member George Stafford, who said it will lead to illegal collusion between shipping companies and large firms that move many employes.

The moving industry sought to exempt coorporate customers from the rules, contending that the big customers will try to use clout to get lower rates than other customers pay.