If on the trial of a person for perjury or for an offence under section 330 (False statement on oath not amounting to perjury)--
(a) the trier of fact is satisfied that the accused has made 2 statements on oath and one is irreconcilably in conflict with the other, and
(b) the trier of fact is satisfied that one of the statements was made by the accused knowing it was false or not believing it was true but the trier of fact cannot say which statement was so made,the trier of fact may make a special finding to that effect and find the accused guilty of perjury or of an offence under section 330, as appropriate, and the accused is liable to punishment accordingly.