I'm an admin of my own form.

In the admin member group I activated "Bypass flood control" and in the staff directory Administrators are unrestricted.

Still when posting a message, and posting one right after, they are merged together.

Am I missing something?

Flood control is about being able to post. It has nothing to do with merging. The latter is only controlled throught the time between the posts.

Ahaaaa.... Thank you.

Is there a possibility to exclude admins from merging?

 

No, either you merge concurrent posts within a time frame or you don't - there is no method to bypass this functionality if it is enabled.

Admins could of course login to the AdminCP, disable the feature, post a second message, then re-enable it.