Too many arguments

Hi

Cut down C8
Single door C12
Double door C14
Sidelite 1 C16
Sidelite 2 C18
Depending on the size of the door P5: P6 is full glass.
What I need is this:
IF C8 = TRUE AND C12 = TRUE THEN D8
IF C8 = TRUE, C12 = TRUE, C16 = TRUE THEN D8*2
IF C8 = TRUE, C12 = TRUE, C16 = TRUE, C18 = TRUE THEN D8*3
IF C8 = TRUE, C14 = TRUE THEN D8*2
IF C8 =TRUE, C14 = TRUE, C16 = TRUE, C18 = TRUE THEN D8*4
Now if full glass is selected then:
IF C8 = TRUE, IF(OR (P5=TRUE,P6=TRUE), C12 =TRUE THEN D8
IF C8 = TRUE, IF(OR (P5=TRUE,P6=TRUE), C12 = TRUE, C16 =TRUE THEN D8
IF C8 = TRUE, IF(OR (P5=TRUE,P6=TRUE), C12=TRUE, C16 = TRUE, C18 =TRUE THEN D8
IF C8 = TRUE, IF(OR (P5=TRUE,P6=TRUE), C14 = TRUE THEN D8*2
IF C8 = TRUE, IF(OR (P5=TRUE,P6=TRUE),C14 = TRUE, C16 = TRUE, C18 =TRUE THEN D8*2

I suggest that you split this down into (at least) 2 stages,
one based on C8,C12,C14,C16 & C18 and the other on P5 & P6
Perhaps you can assign an index to each of the posible combinations of C8,C12,C14,C16 & C18, thus :
IF C8 = TRUE AND C12 = TRUE THEN 1
IF C8 = TRUE, C12 = TRUE, C16 = TRUE THEN 2
etc.
this index can then be passed to different CHOOSE() functions based on the values of P5 & P6.

Am I correct in thinking that when C12 is TRUE than C14 must be FALSE and visa versa? does this allow some simplification.
All your list seems to have C8=TRUE, what happens if C8=FALSE
Note that you dont have to use the IF(C12=TRUE,...,...) construction, if C12 is a logical value then you can just use IF(C12,...,...)