You have to remember barbers used their razors continuously all day for shaves and trims so they would strop before every customer. I still remember seeing that when I was a kid getting haircuts in the 19xx ho hum. Yes they would do maybe a dozen strokes or so. personally I think it was part showmanship like when you go into a japanese restaurant and they cook at your table. Here they would pull up the strop which hung on every chair and slap the razor back and forth. In any case we just shave 1x a day so what is in the barbers Manual does not apply to home use in this case. Or at least that's my story.