The resources tab now has a script you may add to Livesplit to account for load times and splitting. To my knowledge, you must use OpenMBU beta 1.6 specifically, but I have not tested many other versions. It may not work for everyone, so please let me know if that's the case for you.

Once you download and unzip the script file, right-click the Livesplit window and select Edit Layout.

Click the '+' -> Control -> Scriptable Auto Splitter Click the '+' -> Timer -> Timer (2nd timer for game time)

Click Layout Settings and set your 2nd timer's Timing Method to 'Game Time'. The Scriptable Auto Splitter tab has a browse button in which you will select the script you unzipped earlier. Once chosen, the Start and Split boxes should appear.

The timer will start automatically when you enter a level, will pause while you load the level, and splits upon finishing the level (the RTA timer should also be present).

When you practice, you'll want to uncheck 'Start' as it will start the timer upon entering a level.

Since I'm unsure of how universal this script is, RTA will still be the main submission time. Hopefully it works so we can better compare times for different builds + platforms.

If you know more about scripting than I do (and you probably do), please feel free to make a better one!