you can load that bank up to 500 amps (4x125) so should you feed it at 500 amps? I doubt this place draws more than a couple hundred amps, and you're allowed to base the service entrance conductor size on load calcs per nec 230.42(A)(1) so legally I see no problem, and IMO basing SEC size on the rating of the bussbars in the meter pack is both arbitrary and wasteful, if more capacity is needed later, more capacity can be added by a future EC.
-Will
