VBA Code for non easy IF Formula

[Shark Man]

Hay

I hope that you will understand my problem

I have a IF formula that check if “F13” cell is "+" if not do calculation (F13-E13) and stop, if yes go to the previous line and check if the “F12” is "+" if not do calculation (F12-E12) and stop, if yes continuo to the previous cell and so on until you find cell without “+”

The EXCEL IF formula is
=IF(F13="+",IF(F12="+",IF(F11="+",IF(F10="+",IF(F9="+",IF(F8="+",E8-F8),F9-E9),F10-E10),F11-E11),F12-E12),F13-E13)

I'm looking for VBA code with FOR to run and do the same without the limitation of 7 if inside if.

Thanks in advanced
Shark Man