we need to get this shirt & tie thing into context, I'm not talking about the sort of shirt & tie you wear to a wedding but a basic white shirt & a simple tie, yes it does look like a uniform but that's the piont. its about having a professional corporate image.
Its not everyones cup of tea but i bet if their was a poll, the gentlemen who wears a S/T would get the higher price.
plus because you are projecting a more professional image customers believe what you say and more readily take your advice, if i say a stain won't come out the customer believes that the stain won't come out, if I was wearing jeans and a T-shirt and I said the stain won't come out then they might think (that I really mean) I don't have the skill to remove the stain.
Mike