I am trying to make the TODATETIMEOFFSET work inside a case expression. when I try to do this SQL returns me following error. works fine if it's not inside a case expression. What am I doing wrong?

SELECT AP.POR,
       AP.POD Path,
       TODATETIMEOFFSET(AP.StartTime, '-06:00') as StartTime,
       MinimumPrice = (
         CASE WHEN ( CHARINDEX('','' + '''+@Provider+''' + '','', '','' + '''+@UserCompanyList+''' + '','') > 0 ) 
                THEN TODATETIMEOFFSET(AP.MinimumPrice, '-06:00')
              ELSE ( (
                CASE WHEN (getdate() < C.ClearingTime and C.OpenPriceMask = 0)
                       THEN NULL
                     WHEN (getdate() > C.ClearingTime and C.ClearedPriceMask = 0)
                       THEN NULL 
                     ELSE AP.MinimumPrice
                END
              ) )
         END
       ), 
       AP.ClearingPrice,
       AP.PriceUnits
  FROM TES_Auction C
       INNER JOIN TES_AuctionPrice AP ON AP.AuctionID = C.ID

Msg 206, Level 16, State 2, Line 1
Operand type clash: decimal is incompatible with datetime2

also how can I make 'as' syntax work inside a case expression?