SELECT X.*, (X.NewTravelRate - X.TravelRate) AS RateChange FROM (

  SELECT
    UT.TravelRateID,
    UT.UserID,
    U1.FullName,
    U1.VehiclePurchasePrice,
    U1.VehiclePurchaseDate,
    UT.DateChanged,
    UT.TravelRate,
    fnDepreciatedVehicleValue(U1.VehiclePurchasePrice, U1.VehiclePurchaseDate, UT.DateChanged, @nAnnualVehicleDepreciation) AS DepreciatedVehicleValue,
    fnConsultantTravelRate(U1.VehiclePurchasePrice, U1.VehiclePurchaseDate, UT.DateChanged, @nAnnualVehicleDepreciation, @nAssumedAnnualMilage) AS NewTravelRate
  FROM
    taUsers AS U1
      LEFT JOIN taUsersTravelRates AS UT ON (UT.UserID = U1.UserID)
  WHERE
    (U1.Status = 1) AND
    (U1.AllowTravel = 1) AND
    (UT.TravelRateID = (

          SELECT MAX(X.TravelRateID) AS TravelRateID
          FROM taUsersTravelRates AS X
          WHERE
            (X.UserID = UT.UserID) AND
            (X.DateChanged = (
              SELECT MAX(Y.DateChanged)
              FROM taUsersTravelRates AS Y
              WHERE
                (Y.UserID = UT.UserID) AND
                (Y.DateChanged <= @aEffectiveDate)
            ))

    ))

) AS X

ORDER BY
  X.FullName,
  X.DateChanged