My wife has been successfully sued in South Australia by her ex-partner's mother for about $15,000. The original claim for $22,000 was made 05/02/2013, before a change in legislation. The outcome of the trial on 05/09/2014 was a Judgement Amount of $8,300 plus interest of $2,990 with costs to be agreed or taxed. On the advice of the solicitor we’d been seeing about this, we didn’t agree to the costs the plaintiff’s lawyer was asking. On 16/09/2015, an order for costs of $3,389.95 was made. We’ve just got a loan approved to pay the Judgement Debt, now the plaintiff’s solicitor wants an extra $993.73 in interest (10% on $8,300 for 437 days). Are they justified in asking for this?