Aidi....an alternate thought could be considered

& it really depends on the actual hull frame height differential + or - that you have created within your hull frames....
In scratch building I have always considered final deck frame level or heights to be a process that must necessarily be followed & resolved in the final build & not necessarily as provided from the cutting room floor
Take a cork sanding block & cut to 1.5 times the hull frame spacing ...with sanding paper & sand port to stdb across two frames only ......move slowly & progressively onto the next frame FWD & AFT until you can witness a smooth transition between the height of corresponding frames

....
do not try & sand the frames in a FWD to AFT motion
Remember if you find one frame say 1.0 mm lower

....you do not sand all down to that level .....

...but build up that lower frame...... A good way to recheck is to lay a substantial plank fwd to aft & apply as neccesarly minimal pressure to gauge engagement with the frames
Follow these simple time proven thoughts & all will be

.....Derek