The gap between O'ahu's average prices for retail regular gasoline and wholesale regular gasoline fell to 55 cents a gallon during the week ended Sept. 16, the state Public Utilities Commission reported this week.

That was down from a gap of 56 cents a gallon the prior week. Lawmakers mandated the disclosure in hopes it will discourage unfair pricing, after the suspension of controversial gasoline price caps in May 2006.

The average retail price before taxes fell 2 cents to $2.76 a gallon.

At the same time, the average wholesale price fell a penny to $2.21.

The PUC's average wholesale price has been criticized as inaccurate and inflated because it combines different types of wholesale transactions into one price.

Under the program, oil companies must file monthly and weekly reports disclosing in some cases crude oil costs, wholesale prices, gross margins and other figures.