I am pretty certain that it will be. I doubt the 2018 iPhone X Plus will be $1099, meaning it will move into the $999 slot. They have been able to work out the suppliers to negotiate the prices down and since they are ordering two of everything (one part for the X, one part for the X plus).
And that will likely have me upgrade since I am on the iPhone upgrade program and it makes total sense to upgrade to a lower monthly cost with the latest technology.