[Sada]

queryBuildRangeTime = queryBuildDataSource.findRange(fieldnum(ReqPO,RecId));
    if (! queryBuildRangeTime)
        queryBuildRangeTime = queryBuildDataSource.addRange(fieldnum(ReqPO,RecId));
    queryBuildRangeTime.value(strfmt('(("%2" <= "%1") && ("%2" >= "%3"))',toDateReq,fieldstr(ReqPO,ReqDateDlv),fromDateReq));

А так?
Строку нада по моему накладывать не на поле а на RecId