dynamic chart update

Hello to all.
in the attached chart I inserted in define name this formule:

commessa	        =OFFSET(FORMULA!$B$9,,,COUNTIF(FORMULA!$B$9:$B$28,"<>"))			
percentuale	=OFFSET(FORMULA!$F$9,,,COUNTIF(FORMULA!$F$9:$F$28,"<>"))

I don't understand where I'm wrong, the chart doesn't update
adding or removing values
xam