Can I change the default currency on Customer Item Pricing

This is when loading an item price on customer record using the custom price level, the currency defaults to the first currency that exists alphabetically in the currency list, which is Australian Dollar, but the company only sells to customers in base currency of the subsidiary which is New Zealand Dollar. It seems i cannot turn off multi currency for customers so option B is to set the currency on the sublist record to default to the correct currency if possible