Asp.net chart multi-series showing wrong data

After solving this problem with asp.net multi-series chart programmatically, I found another problem in another multi-series chart:

I want to show a monthly sales report, showing the evolution of the last m months in approved and rejected proposals. Some months, there aren't any rejected proposals, so the following query (C#/Oracle) returns some empty results.

select to_char(c.date,'YYYYMM') ctb_month, 
       c.approved,
       count(distinct c.f1) amt_c, 
       count(b.f1) amt_b, 
       sum(nvl(b.value,0)) sum_values
from bens b 
     join contracts c
     on b.contract_id = c.f1
where b.seller = :USR_ID 
AND c.date 
     BETWEEN add_months(:DATAI,:MONTHS) AND :DATAI
group by to_char(c.date,'YYYYMM'), c.approved
order by ctb_month

OBS: Before binding the :MONTHS parameter, I make sure its value is negative.

Example of the query result:

CTB_MONTH APPROVED AMT_C AMT_B SUM_VALUES

201209    APPROVED    10    20    1234.56
201209    PENDING      3     3     120.21
201210    APPROVED    12    18     850.52
201210    PENDING      4     4     158.71
201210    REJECTED     1     1      80.40

NOTE: in this case, there weren't any rejected proposal in 201209 for the current seller.

Code to fill the chart:

I stored the data passed by the lower layers in a var report and filtered the data by it's APPROVED status:

var approved = queryResult
              .Where(r => r.APPROVED == "APPROVED")
              .ToList()
              ;
var rejected = queryResult
              .Where(r => r.APPROVED == "REJECTED")
              .ToList()
              ;
var pending =  queryResult
              .Where(r => r.APPROVED == "PENDING")
              .ToList()
              ;

Then, I'm creating the series in a loop

for (int i = 0; i < 6; i++) {
    Series temp = new Series {
        XAxisType = AxisType.Primary,
        XValueType = ChartValueType.DateTime,
        YAxisType = AxisType.Primary,
        //mostra só a quantidade de contratos
        IsValueShownAsLabel = i % 2 == 0 ? true : false,
        ChartType = SeriesChartType.Column,
        CustomProperties = "EmptyPointValue=Zero",
        Legend = "Legenda"
    };
    grafico.Series.Add(temp);
}

And DataBinding each series by hand

// approved contracts
grafico.Series[0].Points.DataBindXY(approved, "MONTH", approved, "AMT_C");
grafico.Series[0].LegendText = "Cont. approved";
// approved bens
grafico.Series[1].Points.DataBindXY(approved, "MONTH", approved, "AMT_B");
grafico.Series[1].LegendText = "Ben. approved";
grafico.Series[1].ChartType = SeriesChartType.Line;
// pending contracts
grafico.Series[2].Points.DataBindXY(pending, "MONTH", pending, "AMT_C");
grafico.Series[2].LegendText = "Cont. pending";
// pending bens
grafico.Series[3].Points.DataBindXY(pending, "MONTH", pending, "AMT_B");
grafico.Series[3].LegendText = "Ben. pending";
grafico.Series[3].ChartType = SeriesChartType.Line;
// rejected contracts
grafico.Series[4].Points.DataBindXY(rejected, "MONTH", rejected, "AMT_C");
grafico.Series[4].LegendText = "Cont. rejected";
// rejected bens
grafico.Series[5].Points.DataBindXY(rejected, "MONTH", rejected, "AMT_B");
grafico.Series[5].LegendText = "Ben. rejected";
grafico.Series[5].ChartType = SeriesChartType.Line;

NOTES: grafico is my Chart object; Some of the visual settings are defined in the <asp:Chart> tag.

When I run the app, the complete series are correctly drawn, but the incomplete series (201209 / REJECTED, in the above example) is drawn in the wrong X coordinates (the values for 201210 are draw in the column for 201209, in this case), as if the control were ignoring the X values passed in the DataBindXY method and drawing the values in sequence.

Does somebody know how to fix this issue? Thanks in advance.

[SOLVED] Thanks to @jbl, the chart now draws the values in correct places.

The code:

var allMonths = queryResult
    .Select(x => x.MONTH)
    .Distinct()
    .OrderBy(mes => mes)
    ;

foreach (var mes in allMonths) {

    bool hasData = rejected.Any(r => r.MONTH == mes);
    if (hasData == false) {
        rejected.Add(new MonthlyData() { MONTH = mes, APPROVED = "REJECTED" });
    }
    hasData = pending.Any(r => r.MONTH == mes);
    if (hasData == false) {
        pending.Add(new MonthlyData() { MONTH = mes, APPROVED = "PENDING" });
    }
    hasData = approved.Any(r => r.MONTH == mes);
    if (hasData == false) {
        approved.Add(new MonthlyData() { MONTH = mes, APPROVED = "APPROVED" });
    }
}
approved = approved.OrderBy(v => v.MONTH).ToList();
pending = pending.OrderBy(v => v.MONTH).ToList();
rejected = rejected.OrderBy(v => v.MONTH).ToList();

grafico.ChartAreas[0].AxisX.Interval = 1;
grafico.ChartAreas[0].AxisX.IntervalType = DateTimeIntervalType.Months;
grafico.ChartAreas[0].AxisX.IntervalOffset = 1;
grafico.ChartAreas[0].AxisX.IntervalOffsetType = DateTimeIntervalType.Months;

Note: MonthlyData is a simple class that transports the values for every line in the query result.

I guess you will have to use Empty Data Points http://msdn.microsoft.com/en-us/library/dd456677.aspx to align all your series

This would mean :

building a collection of all x values in your series
doing a left join of all these x values with your series to detect all missing points
fill the missing points with empty data points

Hope this will help

edit : you can try (not tested) something like this for the approved/AMT_C serie

var allXvalues = queryResult.select(r=>r.CTB_MONTH).Distinct().OrderBy(month=>month).ToList();


allXvalues
  .ForEach
   (
    xvalue=>
      {
        var p = approved.Where(o=>o.MONTH==xValue).FirstOrDefault();
        if(p==null)
            grafico.Series[0].Points.Add(new DataPoint(p.MONTH,p.AMT_C));
        else
            grafico.Series[0].Points.Add(new DataPoint(xvalue,0){IsEmpty=true});
      }
   );