Working in this field I can say with confidence that it doesn't normally happen like that Julian. Spec up a normal Plus Six and it comes quite a lot more expensive than this LE. MMC isn't the first nor the last to do this.
Update: A normal Plus Six with all the content of the Pinnacle comes out to just over £107,000 and that doesn't account for the bespoke content. They did this with the 4/4 80th Anniversary which had more tat, made it exclusive to just 80 and yet again, priced attractively. I was one of the suckers who bought it sight unseen
Porsche - released a Style Edition based on their entry powertrain to start the send off the 718 will soon have, and I'm certain another LE is around the corner, and it comes out cheaper than a normal base 718 with the same options.
Bentley - launched the Edition 8 as a send off to the last of the V8 and leading up to the newly released GT/GTC/Flying Spur. Much like the Plus Six, it looked and drove like a non-Edition 8 but had unique interior quilting, added content and an attractive price.
Love it or hate it, it's marketing and keeps the factory running and skilled people employed. Considering the market, I for one am happy to see this.