Formula doesn't re-calculate or isn't working properly.

Question

Alright let me first explain the use of this formula so I can explain why it is not functioning properly. Here is this formula
=INDEX('Template Sheet'!$B$1:$S$233,MATCH($A22,'Template Sheet'!$B$1:$B$233,0)+2,LOOKUP(MONTH(DATEVALUE($B$8&" 1")),MONTH('Template Sheet'!$D$1:$S$1),COLUMN('Template Sheet'!$D$1:$S$1))-1)
As it stands the formula scans my first sheet for a task numbers which is in A22 in this example, it then goes to my helper sheet and finds that same number to give us the row (+2 to get the right part of the task). Then it needs to look up the column
it uses the date provided in B8 which is a drop down of just Jan-Dec, then it compares it to my helper sheet again and scans the top row for that date and gives it a column to scan.
Now as of late it is working fine but 2014 is coming up and it is not function properly instead when I try and make it go to 2014 for January, after already deleted the date in the top row, it revers back to the location of where Jan 2013 was sitting, without
any values in that cell. This is confusing me severely...
Alternatives I tried:
1. I tried to add a second drop down with a year value, it ended up not finding any years at all and gave me Value errors
2. I then tried to just use exact date values in the drop down, (I could not solve this one)
Please any advice will help and I can provide more detail to any questions I just need this formula to scan through the dates but it seems like it does not do that function anymore.

Answer 1

Using LOOKUP causes problems with unsorted data - your month numbers are unsorted even though your dates are not. There are other solutions - looking for exact dates, etc., but the best solution depends on what your actual data is. For how you describe your
layout, I think this will work: an array formula (enter using Ctrl-Shift-enter)
=INDEX('Template Sheet'!$B$1:$S$233,MATCH($A22,'Template Sheet'!$B$1:$B$233,0)+2,INDEX(COLUMN('Template Sheet'!$D$1:$S$1),MATCH(MONTH(DATEVALUE($B$8&" 1" )),MONTH('Template Sheet'!$D$1:$S$1),FALSE))-1)