Como hacer la suma del siguiente campo con sqlserver?

[Libras]

Código SQL:

SELECT *, isnull(win,0)-isnull(loss,0) AS resultado FROM(
 
SELECT * 
CASE WHEN RESULT=1 OR tickets=1 THEN SUM(h.winamount) END AS win,
CASE WHEN RESULT=0 OR tickets=0 THEN SUM(h.winamount) END AS loss
FROM(
SELECT CONVERT(VARCHAR(8), H.[SettledDate] , 108) AS 'Time', CONVERT(VARCHAR(MAX),G.[VisitorNumber]) + '/' + CONVERT(VARCHAR(MAX),G.[HomeNumber]) AS 'NumGame', 
       G.[VisitorTeam] + '@'+ G.[HomeTeam] AS 'Teams', CONVERT(VARCHAR(MAX),G.[VisitorScore]) + ' - ' + CONVERT(VARCHAR(MAX),G.[HomeScore]) AS 'Score', COUNT(*) AS 'Tickets',
       SUM(H.[RiskAmount]) AS 'Risk',d.RESULT,h.winamount
FROM  GRADEDGAME G, GRADEDWAGERHEADER H, GRADEDWAGERDETAIL D, AGENT A, WAGERTYPE W
WHERE D.[IdGame]      =  G.[IdGame]         AND 
      D.[IdWager]     =  H.[IdWager]        AND
      H.[IdAgent]     =  A.[IdAgent]        AND
      H.[IdWagerType] =  W.[IdWagerType]    AND
      G.[GradedDate] >= CONVERT(datetime,('2014-01-12 00:00:00')) AND 
      G.[GradedDate] <= CONVERT(datetime,('2014-01-12 23:59:59')) AND 
      W.[Description] NOT LIKE '%PARLAY%' AND 
      W.[Description] NOT LIKE '%REVERSE ACTION%' AND 
      H.[IdAgent] = 5585
GROUP BY H.[SettledDate], G.[VisitorNumber], G.[HomeNumber], G.[VisitorTeam], G.[HomeTeam], G.[VisitorScore], G.[HomeScore], d.RESULT,h.winamount
) AS t1
) AS t2