You need to find out exactly what your old style X-trail weighs. I was in a similar position, concerned about weights, so I took the Xtrail to 2 separate weighbridges and they both weighed it at 1660Kg, no driver but full fuel tank, and an extra jack aboard. This was for a diesel SVE which has running boards fitted. As you have to add at least my weight of 85Kg plus any stuff I put in the car (usually wife!) that makes the actual running weight of the car about 1800Kg. When on holiday we don't carry anything in the car except ourselves.
Our van has MTPLM of 1600, but actually runs at just less than this with all holiday stuff aboard, full gas and bikes. Again this was checked at a weighbridge. This gives a ratio of 89%. With 85Kg noseweight (found to be best by experimentation) we have covered 6000 happy miles so far.
In my opinion the figures given by car and caravan manufacturers can be taken with a pinch of salt until checked on a weighbridge, and if you don't believe the first get a second opinion. Weighbridges charge about a fiver and in my view this is money well spent.
The only factor I havent covered is where the half a ton of booze goes when returning home! In our case it is rear seats folded and just behind us.
Pete