No snottiness intended it was just a very vague thing to say. The short answer is no you do not need an addendum to your license if you do not use RF to bring the RX audio back to the transmitter/comparator. However unless you already have some form of IP service at the locations the added monthly costs can be prohibitive versus just getting an additional link Freq added to your license. I happen to specialize in all the engineering/design of voted systems in your area so feel free to PM if this is something you'd like to explore.For UHF, the best type of antenna
Using a hard wire line or mircowave link, pros/cons
And I don't believe you need a license from the FCC, only transmitting equipment. Is that correct?