Upon a felony conviction of § 18.2-46.2 or 18.2-46.3, where it is alleged in the warrant, information or indictment on which a person is convicted that (i) such person has been previously convicted twice under any combination of § 18.2-46.2 or 18.2-46.3, within 10 years of the third or subsequent offense, and (ii) each such offense occurred on different dates, such person is guilty of a Class 2 felony.