Chart dataset not returning all the data

[Ranga78]

I'm using ireports 4.0.2 and here is my question. I have the main report query which passes two parameters to the dataset query. In the main report I have assigned the parameters in to fields.

$P{Start_date} as Start_Date;

$P{Company} as Company,

and on the dataset, I have defined the parameters with the same name, ie $P{Start_date} and $P{Company}. Added a bar chart to the report which uses the dataset and on "chart data" properties set the following:

Connection/Datasource Expressions: use connection expression $P{REPORT_CONNECTION}

Parameters: $P{Start_date} = $F{Start_Date}  and $P{Company} =$F{Company} ( Fields are taken from the main query)

When run the chart not all data is coming through to the chart. ( only 3 bars are coming through where as there should be 10 on the bar chart)

Any help on why this is happening is much appriciated.