OK, I understand the confusion now. Moiety payments for revenue officers (tax collectors) were stopped in 1871 or 1872, but for customs officers weren't stopped until the Anti-Moiety Act of 1874.  Two separate laws, two separate groups of federal employees.  I'll sort it out in the article, and write some more about Curtis and the Civil Service Commission.  
Calling Chester Arthur a reformer is ... generous.  But we needn't fight over that, since it's beyond the scope of this article.