That's something I've asked before and no one answered me. I decided to screw down the screws entirely and test to see for myself.
With the entire pup at the recommended height (at least on the e strings) I didn't notice any difference. Sounded good but then I started to raise some poles to even out the sound.
In the end I ended up reflushing the screws, lowering the pup a bit and start adjusting the height of the center strings. In the end I got very low height on the sides of the pickup and something more visible on the inside. Took me a bit of lowering and raising the pup but I got pretty much what I had before, it just sounded more balanced (they must have messed up at the factory or something)
I like how it's sounding now but I bet a tech wouldn't do it like this.