This might help further:

Create a named range using Insert Name Define (e.g. call it "Numcols")

=Offset($a$1,0,0,1,counta($1:$1))

Then create a further range for each row of data

=offset(numcols,rownumber,0)

where row number is the number of rows below row 1 for the dat
concerned (ie if you want to plot row 2 then rownumber =1.)

Then plot your charts with the data series as worksheet1!yourdatanam
and x axis as worksheet1!numcols

Every time you add a new column to row 1 then all graphs will updat
and add that column