http://revach.net/article.php?id=893

Section: Halacha   Category: Tshuvos
Be'er Moshe: When You Say "Ritzei" By Melava Malka

Is saying Ritzei unnecessarily a hefsek and you need to say birchas hamazon again? The Be'er Moshe (3:40) says that although the Mogen Avrohom (271:14) explicitly says saying Ritzei is not a hefsek, however we find that the Taz (108:12) disagrees and holds that if you say Yaaleh V'Yavoi" when you don't need to, you must repeat Shemoneh Esrei. Nevertheless says the Be'er Moshe, by Ritzei on Motza'ei Shabbos even the Taz agrees that it is not a hefsek and you need not repeat birchas hamazon.