OFFSET Charts - moving data length
 

I have a set of data in col A [Name] and the data in col C [Cnt] which I have
a bar chart - fine, however col A is currently 10 rows but could grow to 20
rows or more. If I use the formual
=FLUP_Business_Unit!$A$1:$A$20,FLUP_Business_Unit! $C$1:$C$20 then while the
graph looks fine the Legend shows all the Rows that are blank.

I have tried this but it doesn't seem to work.
=OFFSET(FLUP_Business_Unit!$A$1,0,0,COUNTA(FLUP_Bu siness_Unit!$A:$A),1),OFFSET(FLUP_Business_Unit!$C $1,0,0,COUNTA(FLUP_Business_Unit!$A:$A),1)

When I paste into the Data Range it does't seem to save it - Any ideas?
Since it doesn't save I don't know if it is actually correct.