SWITCH function

I'm using Switch function for my worksheet and at some points even simple evaluations bug into zero.

 For example : 

=SWITCH(Baz_Vade;180;R18*$U$8;150;[@[150 gün]]$U$7;120;[@[120 gün]]$U$6;90;[@[90 gün]]$U$5;60;[@[60 gün]]$U$4;30;[@[30 gün]]$U$3)

When I evaluate this at the last step it becomes:

=SWITCH(180;180;3960;150;0;120;0;90;0;60;0;30;0)

yet it calculates into 0. I find this ridiculous. Perhaps I can not see the obvious problem but it doesn't seem like it. 

When I first used the 

=SWITCH(Baz_Vade;"180 gün";R18*$U$8;"150 gün";[@[150 gün]]$U$7;"120 gün";[@[120 gün]]$U$6;"90 gün";[@[90 gün]]$U$5;"60 gün";[@[60 gün]]$U$4;"30 gün";[@[30 gün]]$U$3)

and it evaluated to:

SWITCH("180 gün";"180 gün";3960;"150 gün";0;"120 gün";0;"90 gün";0;"60 gün";0;"30 gün";0)

it again evaluated to 0.

The base problem is the formula is repeated in the predecent formulas so there are circular references. Though the statement of Switch(Baz_Vade) is the key to not get in circular calculations by giving an outside source to iterate the function. I want to know specifically why the ending evaluations I proposed ends up calculated 0. 

Thank you in advance,

mezkur7