Me too. If nothing else, when you're doing multiple submissions, it adds that extra little frisson... will you put the right letter in the right envelope?
Seriously, what IB says is standard format for a business letter. And, if you want to become a publisehd writer, you have to approach stuff like this in a business-like way.
Good luck.
Dee
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<Added>which includes spelling 'published' correctly... !
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