ABV mod for 4AGZE- disconnect ABV?

[Millhouse1]

Many of you have probably heard of the ABV mod, used to take advantage of the additional boost pressure created when fitting a larger pulley. I did this mod a few years back when fitting a 175mm pulley and did notice an increase in power and a slightly more pronounced supercharger whine, but nothing spectacular. I've also read of another approach, which is to remove the ABV altogether and blank it off, supposedly to remove the possibility of any boost pressure being leaked. Today, as an experiment, rather than remove it, I just pulled the pipe off it altogether, so that it's not connected to anything- still fitted, but not connected to anything else via any vacuum lines. Anyway, what a huge difference this has made! Much more power, and a noticeable increase in supercharger whine. However, if it's this simple, why do people bother removing the ABV and blanking it off? And it makes no sense what I've done when I think about it- the ABV is still connected to the supercharger and is therefore now just venting excess boost in to the air instead of back in to the intake manifold (as it does when it's t-eed in doing the regular ABV mod). So why do I now have more boost and whine?

[GDII]

I think it gets removed as eventually the boost pressure will overcome the spring in the unit making it vent anyway.
If it's anything like a BOV on a turbo then that's my understanding of it.