I don't know why but it seems to me you have a problem with the original formula:

=IF((IF(OR(C3=0;B3=0;D3=0;E3=0;F3<=0);0;A4- A3))<0;0;IF(OR(C3=0;B3=0;D3=0;E3=0;F3<=0);0;A4-A3))
if you already check if OR(C3=0;B3=0;D3=0;E3=0;F3<=0) in the TRUE part of the formula, why do you check it second time in the OR(C3=0;B3=0;D3=0;E3=0;F3<=0)
??
If the BLUE condition meets then the RED one is redundant.