if statement working with dates

@ wjalle14:

I believe the problem is in the first part of the IF statement.  There is nothing for the formula to evaluate as "true" or "False" - which is the basis for IF statement.  The portion immediately following If( is:

TEXT(DATE(INT((…….)+1,1),"mmm yyyy")

this portion is simply converting the contents of one of the cells into a text form in the format "mmm yyyy".  What is the IF statement evaluating to get to a "True" or "False" decision?  This is portion of your formula creating the #value error.  Add a decision type statement, your problem would be solved.