Good question, and nice explanation.
Too many people still fall for the claims that Soundex is a phonetic algorithm for indexing by sound and that it's based on American English pronunciation, despite its being extremely flawed for that purpose nothing really based on AmEng pronunciation would return different codes for "sealing" and "ceiling" while delivering the same code for "ceiling" and "killing". That it was originally intened only to be used for names does mean that it's less erratic when used as originally intended, but we still have "Gene" and "Jean" getting different codes, while and "Jean" and "Jane" get the same code as each other, as do "Gene" and "Gawain". It seems quite clear that there was very little attention paid to phonetics in the design of this stuff.
So it's nice to see a QotD that illustrates some of Soundex's failings.