AIB foreign exchange expert Rosemary Murtagh, who gave evidence in July before the tribunal adjourned for the summer break, took the stand in Dublin Castle this morning to be further questioned about this lodgement of more than IR£28,700, made on Mr Ahern's behalf by his then-partner Ms Larkin.
Ms Murtagh, who resumed her evidence shortly after 10.30am, had no contact with the specific transactions undertaken for Mr Ahern in the 1990s and is giving evidence in relation to the foreign-currency systems in the bank at that time.
Incomplete bank records indicate the lodgement was "probably" the result of the conversion of $45,000 into Irish pounds, Ms Murtagh told the tribunal in July. Mr Ahern's lawyers have said the lodgement was £30,000 in sterling cash he had been given by Mr Wall.
In July, Ms Murtagh also agreed with counsel for Mr Ahern that the lodgement "could" have been sterling. Colm Ó hOisín SC, for Mr Ahern, said it could be proven mathematically, based on amounts sent back by a number of AIB branches to the central AIB currency service, that the lodgement had to be in sterling rather than in dollars.
But today Ms Murtagh said that at the time of that evidence while she understood what Mr Ahern's lawyers were saying, she "hadn't seen anything to fully understand what he meant". She said she did not, at the time, have the calculations used by Mr Ahern's lawyers to reach the sterling hypothesis.
Cross-examined later by Colm Ó hOisín for Mr Ahern, Ms Murtagh accepted that an Irish punt sum transmitted to AIB's currency services department from a branch on a given day could in fact have been composed of a number of different Irish punt amounts relating to either sterling or US dollar transactions.
She agreed this was not an option that had been "canvassed" to her by tribunal counsel when she gave evidence in July.
The tribunal heard that sometimes for "manpower" reasons the transactions from a number of different days would be amalgamated and remitted together.
A single "remittance" of Irish punts from a branch to the currency services department could therefore be the sum of more than one sterling or dollar transaction, calculated at different exchange rates.
A letter sent by AIB to the tribunal in September, clarifying aspects of the technical evidence given already by Ms Murtagh, said she had wrongly believed the foreign lodgements went straight from the customer to the foreign note room.
She was unaware of the intervention of a bank teller before that took place.
Ms Larkin, who was involved in a number of lodgements and withdrawals on Mr Ahern's behalf at the time, is scheduled to give evidence tomorrow.
Mr Ahern is due to give evidence on Thursday and Friday. He will be asked about four cash lodgments in 1994 and 1995, all of which were preceded by foreign exchange transactions.
The tribunal heard evidence from a number of AIB bank officials in July, and as that evidence took longer than expected, Mr Ahern's appearance was put back until after the summer break.
In early 1995 Mr Wall purchased a house in Dublin which he at first rented and then sold to Mr Ahern.
In December 1994 Mr Wall gave a suitcase containing £30,000 sterling in cash to Mr Ahern, money that the two men have said was to be used on the renovation of the house Mr Wall was then purchasing.
As well as lodging this money Ms Larkin was also involved in a lodgment in June 1995 that included £10,000 sterling cash and which is also being investigated by the tribunal.
The current sittings are not investigating how Mr Ahern came to purchase his house from Mr Wall, though that issue will be examined at a later date, as is the giving of gifts to Mr Ahern by supporters, and the accumulation of £50,000 in cash by Mr Ahern in the early 1990s.