Development Level is whatever you want to make it and at whatever point.  You could build logic around the level, but there is nothing out of the box that enables or prevents anything.  Says so in the help.

We have these different levels setup and they are process not system driven for the changes between them.  It is entirely up to your engineering process to define.

The Mfg Preliminary Change comes into play during the revision release process, but I can’t find much about it, we haven’t been using it.

@ShawnBerk Thank you for your input.