It's normal to mount the meter centered at 5'. If this is your meter (ie, submetering), there's nothing preventing you from mounting it 1" off the floor if you want to. Utility rules prevail in this situation, but most of them bend when you are faced with an unusual situation and you talk to their engineer first.
You'll have to contact the POCO in your area and ask for their installation manual. Most of the POCO's in my area require the height to be 4'6" to 5'6" to the center of the meter glass unless the meter pan is mounted in or in close proximity to a walkway or driveway in which case they allow you to raise the height to 6'6" to center. This is not an NEC issue but, it is a POCO requirement that your inspector may not pick up on but your POCO will and may not "cut-in" your service.