I am using names andd offset to create a 13 month chart which rolls forward
automatically. however it only updates when a new month is added, i want it
to display the 13 months up to a particular month - held in a separate cell.

currently:

x-axis labels uses the name chtCts
=OFFSET('Data'!$A$3,COUNTA('Data'!$A$3:$A$27)-1,0,-MIN(chtLenn,COUNTA('Data'!$A$3:$A$27)-1),1)

data:
=OFFSET(chtCts,0,1)


table looks like this:
COLA COLB
Month Data
J 3
F 4
M 5
A 6
M .
J .
J .
A
S
O
N
D
J

So at the moment it displays jan to jan, when F is added to above table,
will show feb to feb etc. What i want is to enter a month in a cell, eg M,
and for the chart to display 13 months dependent on this, in this example M
to M. Have tried countif but for some reason there seems to be alimit to the
length of the formula xl2002 will accept as a name. Advice appreciated.