The following exceptions apply to the numbering sequence:
• Names that have letters with the same Soundex number that are separated by a vowel (A, E, I, O, U), then the letter to the right of the vowel is also coded. For example, the Soundex code for Carman is C-655.
• Names that have letters with the same Soundex number that are separated by an “H” or “W”, then the letter to the right of the vowel is not coded. For example, the Soundex code for Ashcroft is A-261. However, this rule was also not consistently applied to all U.S. censuses from 1880 to 1920. Sometimes H and W were treated the same as a vowel. Thus, it is necessary to consider both possibilities. Thus Ashcroft could also have a Soundex code of A-226. This slight variation is officially known as American Soundex or Miracode and it has been used on some U.S. census results. Most people can safely ignore this variation as it only applies to approximately 0.1% of all surnames.