What is THT? Do you mean HHT?

The HHT isn't the end all test. Most razors I've seen that pass the HHT are indeed pretty sharp though, and sharp razors require much less pressure and careful technique. If you start whipping a very sharp blade around your face like you would a so-so sharp blade, you'll definitely be in for some irritation and/or nicks.

Unless by THT you didn't mean the HHT... in which case, what is the THT?

In any event, you should strop before you shave every time regardless of what tests it's passing...