You can check with the manufacturer of the panel, but I promise you no RV maker bothers to do this. It's common guidance for a panel, but if you think about it are you going to make sure you only run your microwave when your AC is on? Or your fridge? Balancing is meaningless when the loads are off. Since you can't (reliably) pre-determine what loads will be turned on or off at any time, breaker panels are always sized to handle a 100% imbalance. That sounds fancy, but is nothing more than making the bus bars thick enough - a bit more copper and they're done. I can't speak for your panel, but it probably is, too, especially if it's UL-listed. The neutral has to be, too.
The only time balancing really matters is if your main breaker is tripping. In that case you sometimes need to move a big load from one side to the other to fix that. But it's extremely rare, mostly because most "big loads" like stoves and clothes dryers in homes are 240VAC (not by accident) and therefore draw from both sides at the same time... and are thus already balanced. I can imagine an over-eager DIY-er throwing in a pile of 120V Mr Cool "self install" mini-split AC's into a house might put all the breakers on one side and cause this, but it's hard to imagine you doing this in your RV especially with a single unit. If you aren't getting nuisance trips, you probably don't have to worry (but I still defer to the manufacturer in the end).
