Which takes precedence?

It was probably around two decades ago that I found myself involved in a machloket (disagreement on a point of halachah/Jewish law) with a then-rabbinical student (long since ordained) hired by my former synagogue to lead Shabbat/Sabbat morning services while the rabbi and cantor were on vacation. That year, a Rosh Chodesh (New Moon, or, roughly, the first day of a new month) fell on a Shabbat on which one of the Haftarot of Consolation was to be chanted. The rabbinical student insisted that we chant Haftarat Shabbat Rosh Chodesh (the reading from the prophets that’s chanted when a Rosh Chodesh falls on Shabbat), but I insisted that the minhag/custom of our synagogue was to chant the Haftarah of Consolation that would normally be chanted on that Shabbat. Much to my dismay, the rabbinical student pulled rank on me, reminding me that he was the Mara D’Atra (roughly, Master of the Place, meaning the one authorized to make halachic decisions). (Grumble.)

Twenty years later, I still think he was wrong, but I think I understand the principle on which he based his decision: I understand that, under many circumstances, an action performed on a regular basis takes precedence over an action performed on a less regular basis. (I’m sure I’ve heard a good Hebrew term for this, but Ms. Middle-Aged-and-Memory-Challenged can’t think of it, of course. Please remind me.) For example, one puts on a tallit (prayer shawl) before putting on t’fillin, even though it’s a pain in the neck to have to keep pulling the tallit back onto to one’s shoulders, because a person who wears t’fillin wears them for weekday morning services only, whereas a person who wears a tallit wears it at every morning service, including Shabbotot/Sabbaths and Shalosh R’galim/Pilgrimage Festivals. Here’s another example: Recently, when Shabbat Rosh Chodesh, for which one reads from an extra Torah scroll, fell on Shabbat Shekalim, for which one also reads from an extra Torah scroll, we did the regular weekly reading first, then the reading for Shabbat Rosh Chodesh, then the reading for Shabbat Shekalim.

But I don’t think this applies to the Haftarot of Consolation for one simple reason—in the case of a haftarah reading, it’s one or the other. (I have heard that. in some congregations both haftarot are chanted, but that’s not the minhag/custom of any congregation to which I’d ever belonged.) So I still think that a Haftarah of Consolation takes precedence over Haftarat Rosh Chodesh.

I would appreciate your comments. I extend a particular invitation to members of the G-d Squad (rabbis, rabbinical students, cantors and cantorial students).