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The HHT is just a test of a single hair, but it does tell you the blade is ready for a shave test.

For the shave test to be "fair" it has to be about the edge and not technique.

What makes...

I'd vote for stropping and stretching as your problem.
Best edge around and slack skin and you get tugging and a rough shave.
Perfect stretching and not shave ready edge and you get...(wait for it)...