MS SQL round on whole numbers during inserting | VBA

I have created a table...

"CREATE TABLE ImportantProcessParameters ([id] int PRIMARY KEY IDENTITY(1,1) NOT NULL,"& _
                "[lot] varchar(19) NOT NULL UNIQUE,"& _
                "[product] varchar(19) NOT NULL,"& _
                "[assay] decimal(10,5),"& _
                "[fpy] decimal(10,5),"& _
                "[na] int,"& _
                "[molar_ratio] decimal(10,5));"

and I insert data from an excel table using vba code. The problem is in molar ratio column, in the excel table I have 8.40 but in SQL this number is 8.00 or if I have 3.42 in SQL it is 3.00. Code that sends data to SQL is bellow

"IF EXISTS (SELECT lot FROM ImportantProcessParameters WHERE lot = "& exLot & ") "& _
"UPDATE ImportantProcessParameters SET product = '"& Empty2Null(exProduct) & "', assay =  "& Empty2Null(exAssay) & ", fpy = "& Empty2Null(exFpy) & ", na = "& Empty2Null(exNa) & ", molar_ratio = "& Empty2Null(exMR) & " WHERE lot = "& exLot & " ELSE "& _
"INSERT INTO ImportantProcessParameters (lot, product, assay, fpy, na, molar_ratio) "& _
"VALUES("& Empty2Null(exLot) & ", '"& Empty2Null(exProduct) & "', "& Empty2Null(exAssay) & ", "& Empty2Null(exFpy) & ", "& Empty2Null(exNa) & ", "& Empty2Null(exMR) & ");"

also i have function to sent null if excel cell is empty

Function Empty2Null(oValue As Variant) As String
        If oValue = Empty Then
            Empty2Null = "null"
        Else
            Empty2Null = oValue
        End If
End Function