Chart based on 'unknown' number of Rows

Hello,

I'm new to Jetreports (but eager to learn and mighty impressed with what i've been shown) and need some assistance.

I have Jet Reports 2010 running with MS Dynamics NAV 2009 R2.

I am trying to create a 'scheduling report' with a chart as a graphical representation of current scheduled work.
The report is based on the total number of minutes that it take for a 'job' to be done (which is based on times specified in the BoM / Route of the Items on the job) and looks forward for the next 14 days (columns in the spreadsheet).

I am using the formula:

=nl("rows","prod. order capacity need","prod. order no.","No.","Mach shop")

to call the Prod. Order No.

and:

=nl("sum","prod. order capacity need","needed time","prod. order no.",$C6,"no.","mach shop","date",D$5)

where $C6 is the Prod. Order No and D$5 is the date (=TEXT(TODAY(),"dd/mm/yy")) +1 etc…

I also have a ROW above this data that reports available capacity: =nl("sum","calendar entry","capacity (effective)","no.","mach shop","date",D5)

I obviously don’t know how many ROWS I will have until I run the report (since it could have 1 Prod. Order it could have 101 Prod. Orders) therefore I am struggling to create a chart that will show me how many Prod. Orders / scheduled minutes I have per day compaired to minutes available.

I’ve tried selecting my rows of data and an additional ‘blank’ line below, assuming that the selected area would expand as the rows expand, but this doesn’t seem to work.

Is there a chosen/specific method I should be using to get this to work?

Any help appreciated.