Max load weight for trailers

Hello, I had hoped to be able to answer my question through the search function, but rather caused more confusion, since I have now read quite contradictory statements.The following: I need a lot of transport space for a move, now the car has a trailer coupling from my father, and I fortunately have the BE appearance.The training is now a little bit since, so I am not sure about the allowed weight.Car data: F.2: 1880kg (total weight) O.1: 12 00kg (max train load with braked trailer) G: 1357kg (empty weight car) So far so good, So how much can I really charge? Let’s assume from a trailer with 300kg of unladen weight. Then I am at: 1880kg – 1357kg = 523kg (additionally loadable weight of the car) 523kg – 300kg = 223kg + 70kg = 293kg (allowed load weight with trailer) 292kg + 300kg are less than the allowed 1200kg, so fully ok. So can in the crew max 293kg? That’s about 200kg of actual load (minus) That would be really a little bit. Do I have a mistake in thinking? Is it easier and I don’t have to assume the total weight, but only the suspension weight (braked there). That would be 1200kg – 300kg = 900kg. That would be easy enough thanks and LG