I think they re-use the shell model for the OHS and the non-OHS seat, so that's why the notch is there. I had one too, it was an August 2005 DOM. I cut it up using my heavy garden by-pass loppers. I was really surprised at how easy it was to cut the plastic between the harness slots. I used the same destruction technique with a 8 year old evenflo infant seat, and the plastic between the harness slots was more difficult to cut as it was thicker. I replaced the Touriva with a Como - that seat has it's issues, but I know that I can't cut it with my garden tools.