(b)in any other case, such interest shall be calculated at the rate of ] [one-half per cent.] [ Substituted by Act 54 of 2003, Section 16, for " two-third per cent."</p>w.r.e.f. 8.9.2003).][for every month or part of a month comprised in the period or periods from the date or, as the case may be, dates of payment of the tax or penalty to the date on which the refund is granted. [Inserted by Act 4 of 1988, Section 98 (w.e.f. 1.4.1989).]