Cyrillic cherv writes the same affricate and, unlike its Glagolitic counterpart, carries a numeral value: ninety. That value is one of the more revealing details in the whole comparison of the two systems. Ninety in Greek arithmetic belonged to a sign that had dropped out of the Greek alphabet as a letter while remaining in the counting, and Cyrillic put a Slavic letter into the vacant slot.
Glagolitic did nothing of the kind, because it was not using Greek arithmetic and had no vacancies. It counted its own letters through to seven hundred and stopped, leaving every Slavic sign at the end of the order unnumbered, this one included.
So the same letter is numbered in one script and unnumbered in the other, and the difference is not an oversight in either. It follows from two different decisions about what a numeral system is for. Cyrillic treats the Greek series as the thing to be preserved and fits Slavic letters into it where it can. Glagolitic treats its own alphabet as the thing to be counted and ignores Greek entirely.
Both names are opaque, and the atlas records that gap rather than filling it.
The pairing itself is secure. Both letters write the same affricate, both stand among the Slavic signs at the end of the order, and both alphabets recite them in the same place. What the atlas does not assert is that either sign descends from the other, because the direction of descent between the two scripts is exactly the question that Slavic palaeography has never closed.