You spot the prices, we ask the questions.

Declan Hayes got in touch to highlight a huge discrepancy he found in the cost of hiring the same car from Hertz through the Aer Lingus website and through the Ryanair website. "I priced an Opel Astra - or similar - for two weeks from Malaga Airport from September 11th to September 25th 2005, by going to the Hertz website via aerlingus.com," he writes. He was quoted a price of €366.21 for the two weeks.

Hayes then priced exactly the same car "with all the same details also from the Hertz website, accessed on this occasion through ryanair.com". The price he was quoted was €468.22, a difference of €102.01. "Both rentals are for the same car, from the same airport for the same amount of time. How can this be explained?"

PriceWatch initially contacted Ryanair about the price difference and was pointed in the direction of Hertz. A spokesman for the car rental company said the discrepancy for the cost of hiring a car via aerlingus.com and ryanair.com was an error. He said that having been alerted to the problem, the company would act immediately to resolve it. "I can't tell you why it happened. It was an error," the Hertz spokesman said.

He said it appeared as if an inaccurate weighting had been applied to the cost of a rental car when users accessed the Hertz online booking facility through the Ryanair website. He added that an investigation would be carried out to establish the source of the problem and to determine if anyone had made arrangements to hire a car from Malaga airport through the Ryanair site and been charged the higher rate. He said that if they had, Hertz would reimburse them.

What's more . . .

Management at the Dundrum Town Centre got in touch in connection with comments from a PriceWatch reader last week about the price of parking in the newly opened shopping centre. The reader expressed concern that an over-park of a matter of minutes could cost drivers up to €5 extra. He said that parking for one hour and 59 minutes would set car park users back €4 while parking for two hours and one minute would cost €9. The management has assured us this is not the case.

"The centre management decided from the outset that an additional hourly charge is not incurred until a 15-minute 'period of grace' has expired," the spokesman says. "So in effect the cost of an additional 15 minutes after the last full hour of parking is free. Therefore the cost of staying for two hours and one minute is €4, and not €9 as reported."

The spokesman says there are three periods of grace. The first is for the 15 minutes after entering - if a car leaves within that time there is no charge. The second is the 15 minutes after the last full hour of parking concludes, and a third is the 15-minute period after a visitor has paid.

"The car park charges are a requirement of the planning permission given by Dún Laoghaire Rathdown County Council," the spokesman says. He also pointed out that there is a charge for parking in the centre of €2 per hour for the first three hours and not two, as reported.

If you notice a significant price increase or discrepancy, let us know by e-mailing pricewatch@irish-times.ie