Interest calaculation for unutilise OD limit amt

Hi,

I need some clarification on interest calculation for unutilise OD limit amount.

For Ex:

I ve created a AA account and ve attached OD limit of 10000 and I ve utilize the 5000 limit amount for that i need to set the 14% rate for calculation. And for 5000 unutilise amount for that i need to set 1% rate of interest .

5000 Utilise amount * 14%
5000 unutilise amount * 1%

Please suggest me how to achieve this.

Please help on this ....

Thanks,