Peculiar behaviour when accessing similar data using functions RIGHT, LTRIM and RTRIM. by Koen Devos

Database table :
CREATE TABLE [dbo].[footbel](
    [divisie] [varchar](50) NULL,
    [datum] [char](10) NULL,
    [hour] [datetime] NULL,
    [home] [varchar](100) NULL,
    [away] [varchar](100) NULL,
    [reshome] [smallint] NULL,
    [resaway] [smallint] NULL,
    [status] [char](3) NULL,
    [md] [varchar](50) NULL,
    [regnumberhome] [char](6) NULL,
    [regnumberaway] [char](6) NULL
) ON [PRIMARY]
GO

The database is filled with a bulk insert from a csv file.
When I look up the table (actually I want to do an Update) I get the following results:

SELECT     TOP (200) regnumberhome, RIGHT('00000' + RTRIM(LTRIM(regnumberhome)), 5) AS regnrH, regnumberaway, RIGHT('00000' + RTRIM(LTRIM(regnumberaway)), 5)
                     AS regnrA, RIGHT('00000' + RTRIM(LTRIM(regnumberaway)), 6) AS regnr6
FROM         footbel
(partial) result :

3855     03855    9446     9446    09446
9567     09567    683     0683    00683
9446     09446    201     0201    00201
683     00683    2982     2982    02982
7436     07436    3554     3554    03554
3182     03182    30        0030    00030
4801     04801    599     0599    00599
3554     03554    9328     9328    09328

In the second column right(rtrim(ltrim(regnumberhome)),5) is the (correct) Number, 5 digits padded 0 to the left of the first database column.

However, for the third column, the same sequence of right(rtrim(ltrim()),5) gives only 4 digits !
I have to add an extra digit (right(rtrim(ltrim()),6)) to get the 5 numbers back !!!

Any advice on the matter ?