Interest at the rate of eight percent (8%) per annum shall be allowed:

1. (a) From the date of settlement on money due on any instrument in writing which does not specify a rate of interest and which is not covered by IC 37-2 or this article;

2. (b) And from the date an itemized bill shall have been rendered and payment demanded on an account stated, account closed or for money had and received for the use of another and retained without the other person's consent.

   Formerly: Acts 1974, P.L.115, SEC.2. As amended by P.L.86-2018, SEC.196; P.L.115-2026, SEC.24.