You spend 20 to 30 minutes to preview and photoread?
It takes me 5 to 10 minutes.
When you photoread you turn one page per minute and you see 2 pages at the same time. So for 200 pages it takes less than 2 minutes.
I'm just a beginner but it's normal to get all the benefits during the activation. When you photoread everything is unconscious.
The benefit of the photoreading step is to have you unconscious familiar with the whole book and while activating it helps you to know what you need to read.
It took me time to understand this because like you while photoreading I didn't find the interest of photoreading. But I'm learning self-hypnosis and I know that the subconscious can do a lot of amazing stuffs.
While turning pages of a magazine, without really reading I've already get words. I've experienced this several times and at this time I didn't imagine that photoreading could exist.
So I'm sure that even if I actually don't clearly feel the benefit of the photoreading I know that it's helpful.
I've read the link you give : I think that this guy has not understood what photoreading is.
He is right thus, that the whole method, even if you don't photoread, can help you a lot. But if you trust the others steps you should trust the whole method and be self-confident while using it.