equal max count per month - what happens, Sql Server

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DECLARE @id int, @first datetime, @last datetime, @name nvarchar(60), @mr int;

DECLARE @UserTable TABLE(
    ID int,
    Name nvarchar(60)
)

INSERT INTO @UserTable (ID, Name) VALUES (1, 'Tester');
INSERT INTO @UserTable (ID, Name) VALUES (2, 'Dummy');
INSERT INTO @UserTable (ID, Name) VALUES (3, 'User');

DECLARE @SampleTable TABLE(
    A_Termin_AE int,
    A_Termin_Status int,
    A_Termin_Set_Date datetime
)

INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 603, CAST('20090525' AS Datetime)); 
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 601, Cast('20090512' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 603, Cast('20090525' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 603, Cast('20100803' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 603, Cast('20100805' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 603, Cast('20100817' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (1, 601, Cast('20110521' AS Datetime));

INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 601, Cast('20090501' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20090502' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20100815' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20110501' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20110505' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20110508' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20110510' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (2, 603, Cast('20110514' AS Datetime));

INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 603, Cast('20120503' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 603, Cast('20120508' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 603, Cast('20120510' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 603, Cast('20120514' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 603, Cast('20120520' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 601, Cast('20130701' AS Datetime));
INSERT INTO @SampleTable (A_Termin_AE, A_Termin_Status, A_Termin_Set_Date) VALUES (3, 603, Cast('20130703' AS Datetime));

SELECT
         Name
       , Mnth
       , Record
       , dense_rank() over(ORDER BY record DESC) RNK
FROM (
        SELECT
                 Name
               , Mnth
               , Record
               , dense_rank() over(ORDER BY record DESC) RNK
        FROM (
                SELECT
                         tu.Name
                       , DATEADD(MONTH, DATEDIFF(MONTH, 0, t.A_Termin_Set_Date), 0) AS Mnth
                       , COUNT(t.A_Termin_AE) AS Record
                FROM @SampleTable t
                JOIN @UserTable tu ON tu.Id = t.A_Termin_AE
                WHERE t.A_Termin_Status = 603
                GROUP BY tu.Name, DATEADD(MONTH, DATEDIFF(MONTH, 0, t.A_Termin_Set_Date), 0)
         ) d1
      ) d2
WHERE rnk = 1
ORDER BY Mnth DESC, Name
;

View schema
Execution time: 0,03 sec, rows selected: 2, rows affected: 25, absolute service time: 0,19 sec