You are overwriting your items.
/writeini [-n] <inifile> <section> <item> <value>
In your case:
inifile is BanList.ini
section is #Michaelukz
item is always $2 (derrick)
Item names in the section need to be unique!
Currently you are doing following:
1) Set item derrick value to be Banned
2) Change item derrick value to be Reason $4
3) Change item derrick value to be TimeBannedFor $3
4) Change item derrick value to be BannedAt $time
