Problem with mailing labels and line feed

I am trying to print mailing labels and suppress optional address lines to eliminate white space while maintaining label alignment.  This is what I am trying but it does not work.

I create a function that determines the length of a field (i.e. street) and increments a counter if the length is zero.  It also takes a second parameter that detremines whether to reset the counter.  I then use the function in the visibility each row of the label table.   Example iif(Code.LineLen(Fields!Street.Value)=0,True,False).  I place this on the visibility of each row except the last as that is City,State,Zip and is required.  On this last row the expession I use is

Public LineCount as Integer=0

Function LineLen(byval LineIn as string,byval IsFirst as boolean) as Integer
if IsFirst=True then

LineCount=1
end if
If len(LineIn)>0 then
LineCount=LineCount+1
end if
LineLen=Len(LineIn)
end Function