Some values change when exported to excell

I have a project in SSRS and one of its function is to calculate the average of the column, when you try to preview the report the calculation is ok but when you export it to excell the value now is wrong.

here is code behind

Public adj as Double
Public curr_adj as Double
Public crown_con as Double
Public curr_crown_con as Double
Public uniformity as Double
Public curr_uniformity as Double
Public tot_quality_score as Double
Public oca as Double
Public crown_defect as Double
Public hid as Boolean
Public defect AS String
Public num AS Integer

Public Function Set_Defect(ByVal d As String)
              num = num +  1
    defect = d
END Function

Public Function Get_status()
    If defect ="BB"
        Return True    
    else
        Return False
    end if
End Function



Public Function Get_crown_defect()
    Return  crown_defect
End Function

Public Function Set_crown_defect(ByVal s As String)
     crown_defect =  crown_defect + CDbl( s)
End Function

Public Function Get_oca()
    Return  oca
End Function

Public Function Set_oca(ByVal s As String)
     oca=  oca + CDbl(s)
End Function

Public Function Get_tot_quality_score()
    Return  tot_quality_score
End Function

Public Function Set_tot_quality_score(ByVal s As String)
     tot_quality_score=  tot_quality_score+ CDbl( s)
End Function


Public Function Get_uniformity()
    Return uniformity
End Function

Public Function Get_curr_uniformity()
    Return curr_uniformity
End Function

Public Function Set_uniformity(ByVal s As String)
    curr_uniformity = CDbl( s)
    uniformity= uniformity+ CDbl( s)
End Function


Public Function Get_adj()
    Return adj
End Function

Public Function Get_curr_adj()
    Return curr_adj
End Function


Public Function Set_adj(ByVal s As String)
                 curr_adj = CDbl(s)
    adj = adj  + CDbl( s)
End Function


Public Function Get_crown_con()
    Return crown_con
End Function

Public Function Get_curr_crown_con()
    Return curr_crown_con
End Function


Public Function Set_crown_con(ByVal s As String)
    curr_crown_con = CDbl( s)


    crown_con = crown_con  + CDbl( s)
End Function

here is the part which returns wrong when report exported to excell

==Round(Code.Get_adj()/Sum(Fields!CountRec.Value, "dSetRecCount"),2)