Mail Forwarding Service accepted by USPS

My friend from NJ is working in Germany.  He wants to have his mail forwarded to a box with a mail forwarding service (cheaper than a PO box or box with UPS) .  I would then pick up the mail at this box at the Mail Forwarding Service.But USPS.com will not recognize the new address as valid because the system knows it is an office building or an industrial area.  He is not able to specify a suite or apartment # to indicate his box.  Has anyone gotten around this?

If he wants to have documents sent from the USA to him in Germany and, for reasons unknown to me, this does not work to this "box", then he should have it addressed to his residential address in Germany (as almost everyone does).

But if this "box" is a mailbox at a regular Germman address, then the German postal services are legally obliged to (and will) deliver there. This cannot be changed by the USA postal service (USPS). So I don't really understand what the issue is.

Sounds like an issue in the States rather then Germany. Ask on the US forum, not here.