So I can't help but notice that depending on the console your load times will be different and from what I can tell here's what I've found out from watching several runs:

Xbox One is the fastest as you can play the digital version from the Hard Drive and due to it's enhancements on the Xbox One X this makes it the quickest version.

Xbox 360 - Either Digital or Installed to the Hard Drive is the quickest option for this console as if you don't install it and just play it via disk the load times are slower by around 2-3 seconds maybe even more.

The IGT runs the same on both consoles (As it should do anyway) so nothing to worry about there.