Cost and forcast budget does not match for certain Task

Hi

When we view the cost budget in Projects its shows a figure that does not match forecast budget and it shows variance

 

Actual hours taken shows correct, according to workplan the cost in forecast budget is not showing correctly

For a project task, certain costs are present in the workplan. same are reflected in the Cost Budget created using the workplan. But when Forecast Budget is created using the same workplan and cost budget, certain resource costs are not correctly reflected

  

Thanks