When does the waiting period (iddah) of a woman whose husband died on the 28th of Shawwal 1440 AH end?

The waiting period ('iddah (definition)) for a woman whose husband has passed away: If she is pregnant, her 'iddah ends upon delivering the entire pregnancy, based on the Almighty's saying: "And for those who are pregnant, their term is until they deliver their burden." If she is not pregnant, her 'iddah is four months and ten days, based on the Almighty's saying: "And those of you who die and leave wives behind - they, [the wives], shall wait concerning themselves for four months and ten [days]." The 'iddah is calculated according to the lunar months, with the obligation to complete the first month to thirty days. So, if the husband died on the 28th of Shawwal, and Shawwal has 30 days, the 'iddah ends on the 8th of Rabi' al-Awwal at the same hour of death. If Shawwal has 29 days, the 'iddah ends on the 9th of Rabi' al-Awwal at the same hour of death.