KING OF THE UNIVERSE III

If you've been keeping up with my blog (first of all thank you so much!) then you know I'm currently reading through The Dark Tower series by Stephen King for the first time. I took a bit of a break between Wizard and Glass and Wolves of the Calla, parts IV and V respectively. Now, I'm back into them. 
Currently, I'm a little ways into Wolves of the Calla Part V of the series. And wouldn't you know it? There's a cameo by good old Mr. Stephen King. I've made posts in the past like this before. Back in 2016 I mentioned how the first book The Gunslinger referenced the movie The Shining. I talked about what that meant for the universe. Read it here. In 2017, I talked about how part of Wizard and Glass made mention of The Stand. Check that out here. 
Now, in Wolves of the Calla there's mention of a bookstore with an advertisement on a chalk board. Which author is featured on this chalkboard? None of than Stephen King. So, I'm confused. The universe where Jake and Eddie come from is the same universe as Stephen King and his books. Presumably, it's our universe as well. Stephen King exists in the universe where he invented things like The Shining, The Dark Tower, and The Stand. Do those books exists in this universe or is it some sort of weird parallel universe to ours where King is an author but some of his major books were never written, such as The Dark Tower series? Or, perhaps in this universe Stephen King has the ability to shine as well. Ugh! 
My mind hurts thinking about this. But I must say, it's fun to think about. What do you think? Have you read The Dark Tower series? What do you think is going on? Let me know in the comments below. Thanks for reading. As always, keep wandering. Just not alone.