IGT is accurate, and takes into account cutscenes but not loads, meaning it equalizes across platforms with different levels of DLC access (such as PC/Switch). While I play on PC, I would like to see this change as it would provide a more level playing field. The only caveat I can see is that it would become very efficient to quit-out in order to refresh skill cooldowns, but that's already always going to be cheaper RTA than waiting for them to refill, so it doesn't really incur a cost as it is.
The load remover used in PC runs has recently been updated to remove dialogue which improves parity between different FPS settings, as dialogue skip speed scales linearly with FPS. Make sure to download the newest version. We are aware there are some instances of dialogue not caught but they should
