In my experience this idea is the best part for matching engine to transmission torque curve. I've done this many times because I can't say a theoretical computation on paper just didn't show real world results until the TC was tweaked after a build....
Saves money in the long run.
I have one in the Hellcat powered CJ7..but that has a 4L80E.
Why anyone would install a TH400 nowadays doesn't make sense if it's driven on the road.