The Mahon tribunal has heard evidence from an AIB bank official that could conflict with explanations the Taoiseach gave regarding payments it is currently investigating.
Today the tribunal examined a payment of almost IR£29,000 lodged into an account belonging to Mr Ahern's then-partner Celia Larkin on 5th December 1994. Mr Ahern claims that sum was comprised mostly of sterling and was received from Michael Wall for the payment of stamp duty on a house.
However, the tribunal's calculations had found this amount equates to a lodgement of $45,000, based on exchange rates in use at the time.
John Garrett, who was put forward by AIB as a foreign exchange expert and in the computerised system used by the bank in mid-1990s, agreed that bank records for the AIB branch at 31-33 O'Connell Street from 5th December 1994 show that sterling notes equivalent to the value of IR£1,921.53 were transacted on that day.
On the same day the foreign exchange account for currencies other than sterling showed the equivalent of close to IR£29,000 had been transacted.
However, Mr Garrett said that because tally rolls for the period were unavailable he could not definitively say in what currency the amounts in question had been deposited in the foreign exchange account, and which rate applied to them.
Mr Garrett also pointed out that for transactions over a certain amount, bank employees needed to obtain a special rate for the transaction, something that could have affected the rates applied to the transactions that would not have been available to the tribunal.
He also refused to rule out that an error in the rate applied may have been made by bank officials at the time.
In a statement on May 13th, Mr Ahern denied that he had ever made a dollar lodgments to his account.
"I never had $45,000 either then, before then or since. There are no dollar transactions in my accounts. I do not deal nor have I ever dealt in dollars," he said in his statement.
This afternoon the tribunal also dealt with a payment lodged into Mr Ahern's account on October 11th, 1994 of almost IR£24,838. This sum of money is referred to as the Manchester dinner lodgment.
Mr Garrett agreed that the amount of sterling purchased by the O'Connell St branch was sufficient to have allowed for the IR£24,838 to have been a sterling amount - provided that the records presented were accurate. However, once again he refused to rule out that a special rate could have been applied to the transaction.
