Maybe this is a dumb question on my part, but why would you want to "Preload" the next tool?
When changing a tool you need to drop off the old one prior to picking up the next one. On some of the machines that I have seen with High Speed Tool Changers, there was code at the begining of the program that set the order of the tools so the next tool was automatically "Prestagged". Others I have seen there was a specific M code that you had just after a tool change that "Prestagged" the nest tool. Are you doing this because of a High Speed Tool Changer?
Motion Master 5 Axis Router.......Fagor 8055/C.......Surfcam Velocity 4.0 B189