Estimativa de linha incorreta seguindo o operador Compute Scalar no plano

Estou lutando para entender de onde vem uma estimativa de linha em um plano de execução.

Cole o link do plano

declare
@BatchKey INT = 1, @ParentBatchKey INT = 1,
@QuoteRef varchar(50) = 'Q00018249',
@MpanRef varchar(50) = '1425431100004'


SELECT DISTINCT
        ISNULL(c.ContractReference,-1) AS [ContractReference] ,
        ISNULL(d_cd.ContractDetailsKey,-1) AS [ContractDetailsKey] ,
        -1 AccountManagerKey,
        -1 SegmentationKey,
        ISNULL(d_tpi.TpiKey,-1) AS [TpiKey] ,
        ISNULL(d_cu.CustomerKey,-1) AS [CustomerKey] ,
        ISNULL(d_p.ProductKey,-1) AS [ProductKey] ,
        -1 as PayPointKey,
        -1 AS [GspBandingKey], --Not used in Junifer ESOB
        ISNULL(d_pps.[ProductPricingStructureKey],-1) AS [ProductPricingStructureKey],
        ISNULL(d_tou.TouBandingKey,-1) AS [PricingStructureBandingKey],
        -1 AS [VolumePointCategoryKey],
        ISNULL(d_ppc.PowerPeriodCategoryKey,-1) AS [PowerPeriodCategoryKey],
        ISNULL(d_pcat.[PriceComponentAggregationTypeKey],-1) AS [PriceComponentAggregationTypeKey],
        -1 AS [MarginRateBandingKey], --Not used in Junifer ESOB
        -1 AS [DuosUrcBandingKey], --Not used in Junifer ESOB
        -1 AS [ConsumptionToleranceKey],
        ISNULL(d_mp.MeterPointKey,-1) AS [MeterPointKey] ,
        ISNULL(d.DateKey,-1) AS [ForecastDateKey] ,
        -1 AS [ForecastEFADateKey], 
        ISNULL(d_cw.DateKey,-1) AS [ContractWonDateKey] ,
        ISNULL(f.SiteVolumeKwh,0) AS [SiteVolume] ,
        ISNULL(f.GspVolumeKwh,0) AS [GspVolume] ,
        ISNULL(f.NbpVolumeKwh,0) AS [NbpVolume],
        @BatchKey,
        @ParentBatchKey,
        CAST(f.ForecastKey as NVARCHAR(100)) AS [SourceId]
FROM 
        [Electricity].[Forecast] f 
              INNER JOIN Electricity.ContractMeterPoint cmp ON cmp.MeterPointKey = f.MeterPointKey and cmp.ContractKey = f.ContractKey  
              INNER JOIN Electricity.Contract c on c.ContractKey = cmp.ContractKey 
        INNER JOIN Electricity.MeterPoint mp ON mp.MeterPointKey = cmp.MeterPointKey

        --INNER JOIN Electricity.ContractMeterPoint cmp ON cmp.MeterPointKey = mp.MeterPointKey and cmp.ContractKey = c.ContractKey 
        INNER JOIN Electricity.ProductBundle pb ON c.ProductBundleKey = pb.ProductBundleKey
        LEFT JOIN Electricity.Quote q ON c.QuoteKey = q.QuoteKey
        LEFT JOIN Gdf.Tender t ON q.TenderKey = t.TenderKey
        LEFT JOIN Gdf.Customer cu ON q.CustomerKey = cu.CustomerKey
        LEFT JOIN Electricity.ProductBundleAggregationType pbat ON pbat.ProductName = pb.BundleName
        LEFT JOIN Dimensional_DW.DimensionElectricity.Product d_p ON d_p.ProductDurableKey = pb.ProductBundleKey
        LEFT JOIN Dimensional_DW.Dimension.Tpi d_tpi ON d_tpi.TpiDurableKey = c.TpiKey
        LEFT JOIN Dimensional_DW.DimensionElectricity.ProductPricingStructure d_pps ON d_pps.ProductPricingStructureDurableKey = f.PriceStructureKey
        LEFT JOIN Dimensional_DW.DimensionElectricity.TouBanding d_tou ON d_tou.TouBandingDurableKey = f.PriceRateKey
        LEFT JOIN Dimensional_DW.DimensionElectricity.MeterPoint d_mp ON d_mp.MeterPointDurableKey = cmp.MeterPointKey
        LEFT JOIN Dimensional_DW.DimensionElectricity.PriceComponentAggregationType d_pcat ON d_pcat.[TnuosAggregationType] =pbat.[TNUoSAggType] AND d_pcat.[DuosAggregationType] =pbat.[DUoSFixedAvailAggType] AND d_pcat.[DuosUrcAggregationType] =pbat.[DUoSURCAggType] AND d_pcat.[BsuosAggregationType] =pbat.[BSUoSAggType] AND d_pcat.[ROAggregationType] =pbat.[ROAggType]
        LEFT JOIN Dimensional_DW.Dimension.Date AS d ON d.DateKey = CAST(CONVERT(NVARCHAR(8), f.DeliveryDate, 112) AS INT) 
        LEFT JOIN Dimensional_DW.Dimension.Date AS d_cw ON d_cw.DateKey = CAST(CONVERT(NVARCHAR(8), c.QuoteWonDate, 112) AS INT) 
        LEFT JOIN Dimensional_DW.DimensionElectricity.PowerPeriodCategory d_ppc ON d_ppc.HhPeriod = f.Period
        LEFT JOIN Dimensional_DW.Dimension.Customer d_cu ON d_cu.CustomerDurableKey = cu.CustomerKey
        LEFT JOIN Dimensional_DW.DimensionElectricity.ContractDetails d_cd ON d_cd.ContractDetailsDurableKey = c.ContractKey

WHERE  1=1
   and     c.ContractReference = @QuoteRef
   and c.QuoteWonDate IS NOT NULL 
   and c.QuoteKey <> -1
           --(SELECT distinct C.ContractKey FROM Electricity.Contract WHERE ContractReference = @QuoteRef and c.QuoteWonDate IS NOT NULL and c.QuoteKey <> -1)
                --(SELECT distinct C1.ContractKey FROM Electricity.Contract c1 WHERE c1.ContractReference = @QuoteRef and c1.QuoteWonDate IS NOT NULL and c1.QuoteKey <> -1)
        and mp.MpanID = @MpanRef
              --and c.ContractKey = 18235
              --and d.DateKey =  20180522
              order by [ForecastDateKey]

Meu problema é em torno do nodeId 26, o operador escalar:

Não tenho certeza de como a estimativa de linha de 5 está sendo gerada - isso parece cascatear o plano para a maioria dos outros operadores - as contagens de execução estimadas dos operadores de loop aninhado mais abaixo no plano parecem indicar ~ 5 estimado, então ~ 35k reais.

Por que o operador escalar seria alimentado com uma estimativa de ~14.000 linhas e, em seguida, estimaria uma saída de 5? Isso é um problema ou um arenque vermelho? Tem alguma coisa a ver com as conversões que está realizando? Eu posso entender isso afetando uma junção, mas por que isso afetaria a saída da conversão?