Is there a regulation/policy stating "the higher ranked soldier will be the sponsor of a dependent"?

My husband and I joined the military (already married), and had our son when we were both E-4's. Since we were the same rank, I took sponsorship of him. Presently, I'm an E-5 and my husband is an E-6, we just PCS'd and are having issues with "his" command. We turned in our family care plan, and since I am the sponsor of our son, my name is on all the paperwork. However, it seems his CDR finds this inadequate and told him he has five days to switch our son in DEERS so that he is under his name, and redo the FCP paperwork to match the change. We've never had an issue with this from previous commands, and I can't seem to find anything on the web involving a regulation stating one way or the other. We know that for the financial aspect it would make more sense to transfer, however we don't want to continue switching back and forth as we out rank each other throughout our careers.

Is there a definite answer, or someone that knows where I can find the information. TIA.