Coachman 2 berth double bed

We have a 2017 Coachman Vision 450 2 berth.  We have been very puzzled by the arrangement for making up the 2 single beds into a double.  In all our previous vans we have placed the backrest cushions in the centre with the seat cushions nearest to the outside walls of the van and with the raised part of the cushion closest to the wall.  In the Coachman it is almost impossible to do that as the cushions are such a tight fit.

I contacted the dealer who contacted Coachman and I was sent a photo of how it should be done. The theory is that you put the back rest cushions closest to the walls of the van and the seat cushions in the centre with the raised part nearest the walls of the van.  However, we cannot make that system work as the raised part of the cushions results in an uneven bed base.

I have written to Coachman about it and had a reply saying that their instructions are correct.  I have phoned but find they are closed for the w/e so will try next week.

Meanwhile does anyone else have a Coachman with a similar challenge`?