not sure if this is what you are after, this was my first guess

/*--Results

ClosestUnder ClosestOver

20 25

*/

;WITH MyCTE([Code],[Number],[Value])

AS

(

SELECT '5',convert(float,'10.00'),convert(money,'1.9201') UNION ALL

SELECT '5','15.00','1.9100' UNION ALL

SELECT '5','20.00','1.8937' UNION ALL

SELECT '5','25.00','1.8589' UNION ALL

SELECT '5','30.00','1.8700'

)

SELECT MAX(ClosestUnder) AS ClosestUnder,max(ClosestOver) AS ClosestOver

FROm (

SELECT MAX([Number]) As ClosestUnder,NULL ClosestOver FROM

MyCTE T1

WHERE [Number] <=20.7

UNION

SELECT NULL As ClosestUnder,MIN([Number]) ClosestOver

FROM MyCTE T2

WHERE [Number] > 20.7

) MyAlias