On Thu, 20 Oct 2016 20:59:43 -0700 (PDT), wrote:

Always in the service the neutrals and grounds are bonded together with bonding screw inspectors want neutrals on one side grounds on the other it would not mater because the bonding screw bonds all together this is just at service at sub panels there seperated

It matters because you do not want circuit current flowing through
that screw. (250.6)
You put neutrals on the neutral bus where the service neutral lands
and you can put the grounds there or on the grounding bus(es).
Generally it is best to use the grounding bus and save any unused
neutral bus holes for future expansion.