This is a design issue. Are you refering to the POCO xfr?? Our utility co's here routinely install 'small' transformers (13.2 to 480/13.2 to 120/208) on their supply side.
That said, do you have any capacity for future expansion, if you opt for the smaller unit that you reference as 'close'?
IMHO, a good design would allow for future capacity, unless this resi is being built with no possibility for any significant future electrical requirements. (Such as resi apts)
