In a situation where only single-character replacements, insertions, and deletions are significant and transpositions are not, the pure Levenshtein Distance algorithm may perform better than the Damerau-Levenshtein Distance algorithm. This is due to the fact that the Damerau-Levenshtein Distance algorithm also incorporates the transposition operation, which enables the switching of neighboring characters.
For the signup, I assumed that only account numbers are unique and I test against duplication.