This was always my argument, too. Whilst I used reflux milk, both Enfamil AR and SMA staydown, BOTH tins say to use cold water (otherwise its too thick), I used to use room temperature.
Now my argument is these are not made in any different conditions than 'standard' milk, and in fact probably exactly the same factory/line. I cant see there being anymore of an issue using cooled boiled between the two, except one advises it and one doesn't.
That said, its your call, you do what ever you are comfortable with, and if you don't want to do the nights as recommended you could always try the cartons instead?