If you had used 1 then the initial access level would be replaced. The =1 means that the initial general access level is not replaced. This looks like the above command, however the =1 is very important.

If the user does not exist, it is created. This adds the specified levels to this user. This adds this nick with these access levels to the user list (replacing an existing user of the same name). Remember, if the first level is not preceded by an equal sign then it is a general access level. If you specify, then if the user already exists, the specified levels are added to the current levels the user has. This adds the specified nick/address exactly as it is given to the users list with the specified levels. You can use the following three commands to add and remove users to the users list, as well as to add and remove levels from existing users. This displays a list of either all, enabled, or disabled groups in your scripts. You can also specify a wildcard to disable all matching groups: This disables the specified groups in all scripts. You can also specify a wildcard to enable all matching groups: This enables the specified groups in all scripts. You can find out about groups in the Access Levels section. These commands allow to turn groups on and off in remote scripts. This switches processing of all scripts on/off. This switches processing of numeric events on/off. This changes the default user level to the specified level. This switches processing of named events on/off. This switches processing of ctcp events on/off. The following commands are used to modify settings in scripts and in the remote section.

Mirc commands for operators