I have no actual proof from testing but I think that the negative to lens distance is much more critical than the lens to paper distance.
I thought that the distance neg. <—> lens and the distance lens <—> paper are 'reversed proportional' ( is this the right expression in English?) to each-other. So, when one of the two distances is wrong the other one is equaly wrong, or am I wrong?
"...If you can not stand the rustle of the leafs, then do not go in to the woods..."
(freely translated quote by Guido Gezelle)
PS: English is only my third language, please do forgive me my sloppy grammar...