When the load of gasoline arrived at the Boston service station Saturday at 2 a.m., it was not priced.

And when the service station opened at 6 a.m., owner Larry Cresta was still in the dark about what his supplier planned to charge for that portion of the day's supply.

"Finally, I received an answer at 10:30 in the morning -- 4 1/2 hours after I opened -- only to find out my cost of fuel had gone up 5 1/2 cents," Cresta said yesterday. "It's not a happy position to be in."

"We're kind of trapped in the middle... . The dealer is probably just as confused as the consumer," he told the House Subcommittee on Energy and Power yesterday about the rapid-fire increases in the price of oil and gasoline.

The sudden run-up in gasoline prices has created a volatile mixture of confusion and anger, with most of latter directed at oil companies whose representatives were called to Capitol Hill yesterday to explain themselves.

The price increases may have created as much as a $1 billion windfall for oil companies, Rep. Ron Wyden (D-Ore.) said yesterday, based upon the size of the recent price increases and the amount of petroleum inventories.

"Saddam Hussein may not be the only greedy person in this picture," said Rep. Phillip R. Sharp (D-Ind.) at a hearing yesterday on oil prices.

The industry's chief lobbyist, Charles J. DiBona, president of the American Petroleum Institute, said that some of the criticism reflected "a naive and one-sided view of how markets work."

Since Aug. 1, the market has increased the price of self-serve unleaded by 12.6 cents nationally, ratcheting it up to $1.21 -- the highest level in nearly five years, according to the American Automobile Association. And further price increases are anticipated.

Both consumers and service station operators have been bombarded with price increases. "Gasoline dealers in my part of the country literally are climbing the ladders to change prices twice a day," said Rep. Doug Walgren (D-Pa.).

Service station operators changing their prices that often may be reflecting the rapidity with which their costs have gone up. High-volume service stations may get two or three loads of gasoline a day and even those with the lowest volume get at least two deliveries a week, according to Jim Daskal, general counsel to the Service Station Dealers of America. A dealer who gets an unpriced delivery, as Cresta did, may be caught short if he sells it at the previous day's price.

The frequency with which service stations receive deliveries may also account for disparities between stations selling the same brand, Daskal said.

Service station operators are getting supplies from refineries that were running at more than 93 percent of capacity -- the highest rate since 1977. Inventories of gasoline are also at historic lows, according to industry officials.

Those refineries, which are producing everything they can and selling everything they produce, now face the prospect of buying crude oil at sharply higher prices. Crude oil that was selling for less than $16 a barrel in June was selling for $28.31 yesterday.

In effect, refiners are in a situation analogous to someone who bought a house for $40,000, then put the house on the market in anticipation of buying a similar house in a market in which such houses now command prices of $300,000.

Critics of the oil industry argue that oil companies are demanding high prices for gasoline that was refined from oil bought at lower prices just weeks ago. "Our people are very upset about the whole process," said Daskal. "Traditionally, when crude prices fall our people are told that it takes 45 to 60 days" to be reflected in wholesale prices for gasoline, he said. "Today, when crude prices are climbing, what they are telling us is that they have to price the gasoline not on what it cost them to produce but on what they have to pay to replace it."

A Texaco official said that despite the recent escalation at the pump, gasoline prices are still lagging behind prices for crude oil from which the gasoline was refined. "Crude oil prices have risen more than 50 percent since early July, while retail {gasoline} prices have gone up significantly less," said Glenn F. Tilton, president of Texaco Refining and Marketing Inc.

Oil industry officials also respond that the price of the crude oil deliveries refiners receive is no longer based on predictable long-term contracts under which prices remain unchanged as tankers steam from port to terminal. Instead, most cargoes are priced according to the values on the spot market on the day the oil is delivered.

"Significant market-influencing quantities of oil and product entering U.S. refineries or distribution systems today are paid for at today's price, not the price 45 days ago," said Tilton. In Texaco's case, because it sells more than it refines, 60 percent of what it sells is purchased "on the open market at prevailing prices," he said.