House Armed Services Committee Chairman Les Aspin (D-Wis.) said yesterday major discrepancies have become apparent between U.S. and Kuwaiti interpretations of the plan for U.S. naval escort of Kuwaiti oil tankers through the Persian Gulf and that more American forces than previously envisioned may be needed.

Aspin said the differences emerged in a meeting Saturday between Kuwaiti officials and a delegation of House Armed Services Committee members who traveled to the Persian Gulf during the Fourth of July congressional recess.

At a Capitol Hill news conference yesterday reporting on the results of his trip, Aspin said it was not clear whether the U.S. or Kuwaiti interpretation would prevail. But he predicted the discrepancy could lead to possibly substantial delays in the Reagan administration's reflagging and escort operation, due to start July 16, if Kuwait prevails.

"If the Kuwaitis are right and we accept their plan and we have to go back to the drawing boards, the chances of this escort operation taking place anytime soon are pretty near nil," he said.

In explanations to Congress, Aspin said, U.S. officials had outlined a plan under which 11 Kuwaiti tankers would have U.S. escort through the Persian Gulf as they make round-trip voyages to their final destinations, such as distant European ports.

But, he said, the Kuwaitis said their plan calls for a shuttle operation in which the 11 escorted tankers would travel only to a point just outside the gulf, Khor Fakkan in the United Arab Emirates, where the oil would be transferred to other vessels. The tankers would then return to Kuwait for more oil.

This plan would greatly increase the number of convoys per month and thus increase the number of U.S. escorts. An Aspin aide said instead of the five round trips per month the U.S. Navy had scheduled, it might take up to 10 per month to meet the Kuwaiti plan.

The aide said that instead of U.S. warships escorting 35 percent of all Kuwaiti exports they might be protecting as much as 70 percent.

However, Assistant Secretary of Defense Richard L. Armitage told the Senate Foreign Relations Committee June 16 that the 11 Kuwaiti tankers to be protected by U.S. warships would be carrying 65 to 70 percent of total Kuwaiti exports. Thus, it was not immediately clear to what extent the U.S. and Kuwaiti plans may be at odds.

Aspin said it was not clear how Iran, which has been attacking other nation's ships when they call for oil at Kuwaiti ports, would react if so much of Kuwait's oil is put under U.S. protection. "The key fact is that the U.S. Navy should determine when it can and cannot escort . . . . Kuwait should not control the schedule," he said.

Aspin's disclosure came as the House and Senate prepared to debate legislation expressing congressional opposition to the reflagging operation, although leaders of both chambers have said Congress can do nothing at this point to block the operation if the administration is determined to proceed with it.

In the Senate, Democratic leaders also conceded they lack the votes to end a GOP filibuster against a nonbinding resolution calling on the administration to hold the reflagging plan "in abeyance" pending diplomatic and other efforts to end hostilities in the Persian Gulf region. They were seeking compromise language acceptable to Republicans before a scheduled cloture vote to cut off the filibuster today.

The House was to vote today on measures that would delay the operation for 90 days or block it indefinitely. The 12-member House Armed Services Committee delegation to the gulf said it would oppose the blocking action, but Aspin said he would vote for the delaying move in light of the fact that the United States may have to "go back to the drawing boards" on the policy in any case if Kuwait's interpretation of the plan prevails.