I am currently using the following formula and it gives the result P-10, P-10, P-11 below dates that are manually entered. I can not figure out why the date 10/31/09 returns a P-11 value when it matches a P-10 value? All other dates work expcept for the 12 period ending dates. Any help would be greatly appreciated.
=INDEX($B$5:$B$16,MATCH(A$1,$A$5:$A$16,1)+1,0)
10/17/09 10/24/09 10/31/09
P-10 P-10 P-11
01/31/09 P-01
02/28/09 P-02
04/04/09 P-03
05/02/09 P-04
05/30/09 P-05
07/04/09 P-06
08/01/09 P-07
08/29/09 P-08
10/03/09 P-09
10/31/09 P-10
11/28/09 P-11
01/02/10 P-12
=INDEX($B$5:$B$16,MATCH(A$1,$A$5:$A$16,1)+1,0)
10/17/09 10/24/09 10/31/09
P-10 P-10 P-11
01/31/09 P-01
02/28/09 P-02
04/04/09 P-03
05/02/09 P-04
05/30/09 P-05
07/04/09 P-06
08/01/09 P-07
08/29/09 P-08
10/03/09 P-09
10/31/09 P-10
11/28/09 P-11
01/02/10 P-12