Once more we have a problem with a versus o in the name for a monetary unit. Here scribe 2 of 𝓟 first wrote omnor; then he himself corrected it to amnor. Later, while proofing against 𝓞, Oliver Cowdery crossed out scribe 2’s corrected amnor and supralinearly wrote the a as an o; but then Oliver himself changed his mind and corrected his own omnor to amnor (by supralinearly writing out the whole word). Obviously, both scribe 2 and Oliver Cowdery had difficulty interpreting how Oliver had written amnor in the original manuscript (which is not extant here). But since both scribes ended up deciding that amnor was correct, the critical text will follow their final interpretation. In addition, the word appears earlier in verse 6, and there scribe 2 wrote amnor without correction as “an amnor of silver”. Perhaps in verse 11, 𝓞 actually read omnor and the corrections in 𝓟 to amnor were the result of scribe 2 and Oliver Cowdery independently referring back to the first occurrence of amnor in verse 6, spelled correctly there in 𝓞.
Summary: Retain amnor, the uncorrected spelling in Alma 11:6 and the twice-corrected spelling in Alma 11:11 (originally by scribe 2 of 𝓟 and later by Oliver Cowdery).