That and the game can flag frames that are too different (camera cuts) to mitigate this problem.
What the game supplies is the current frame + motion vectors, but the framegen bits take over how the frames are displayed onscreen. This is where the extra latency comes from, at worst you are seeing one true frame behind what the game is rendering, while the presentation layer generates the intermediate frame(s).
It is generally a bad idea to do that nowadays, because it ties you forever to that controller. If it dies you will need to find an exact replacement or accept that the whole array is lost. With software raid you can run any hardware.
Wendell from Level1Techs is a good reference:
https://youtube.com/watch?v=l55GfAwa8RI
https://youtube.com/watch?v=Q_JOtEBFHDs
BTW: good score, you will have fun with those for sure.