What did I do? Help?

If you're using one of those FBO limiter plates, they are not accurate at all. They provide more advance than they say. EDIT: But I'm sure that alone is not causing what you're describing. It's gotta be something simple. You'll get better, more-accurate results by welding up your slots. I tried an FBO plate with poor results also and posted about it as well in this guy's thread.
You should read through this thread:

https://www.forabodiesonly.com/mopar/threads/fbo-plate-over-advancing.548564/