I wanted to know whether what I’ve been doing is correct: I finish Shabbos at 72 minutes as a chumrah, but I do derabannans from 60 minutes, relying on safek derabannan lekula and meiikar hadin I follow R’ Moshe to finish Shabbos at 50 minutes.
Thank you very much!
There are numerous poskim who say that one should wait until 72, however if you are going according to R’ Moshe zt”l then it sounds like you cheshbon is correct. It would be noteworthy though that if there are children or other people that will see you doing d’rabonons before the time that they think shabbos finishes, and they will not know the difference between a d’rabonon or a d’orayso. They might get the message that before the end of shabbos we can “cheat” a few minutes and really do melacha earlier, which would be portraying the wrong ideas to them.