Here is the Shrock Manufacturing Inc. / Elkhart, IN 46515 (219) 264-4126, sofa mechanism on my 2000 380DA, yours may be similar.
There is not any adjustable stop on the mechanism, to position the endpoint of the cushion movement at a different location.
On my boat, the upper cushion has a rounded surface at the top (when configured as a sofa), so even though the cushion lays flat when configured as a bed, that rounded top makes the surface not flat.
[img]https://live.staticflickr.com/65535/48666441008_a84ed3def6_b.jpg[/img]
One option would be to add a stop in the track, so it is prevented from fully reclining.
Another (easier) option would be to remove the upper cushion from the arms, then insert spacers between the cushion backer board and the arms, to attain a different angle, when used as a sofa and when used as a bed.
