It's a common objection.
'This modern style of writing is all very well, but...
I work in enforcement/my stuff might go to court/I want to show I'm being professional.'
Time for some plain English. I'm going to be less diplomatic than I would be in a workshop.
Let's get controversial.
Business letters in formal English are not more professional. They're just odd. They're not better service; they're aloof and cold and say, 'This is our routine letter because we couldn't be bothered writing one especially for you'.