GOD! i seriously think you're overestimating/theory crafting the potential of anti-powerfshield tactics.
First of all, Theory crafting how you could potentially shoot lasers as falco and then avoid a powersheild is kinda silly.
You're making it sound like you can react to a powershield on reaction, which you simply cant at any distance except far away. And if your opponent is going to powershield lasers from across the stage then who cares whether they do it or not it doesnt even matter. unless you just EXPECT the laser to be PS'd then you best option is probably just to PS it right back.
PS'ing only affects falco when he's on the approach or your opponent is doing running PS approaches. in both cases, it is incredibly difficult to theory craft things such as "Im going to shoot this laser really low then SH over the powershield for teh mindgames" midmatch because frankly if your opponent is already close enough that a PS'd laser will be bad for you and you think you need to take anti-Ps measures, then you're probably ALREADY ****ed anyway.
What im saying is, in any situation where a PS laser would mess you up, coming up with a anti-Ps strat such as shooting them really low or really high in the event you can jump over it or crouch it, there are probably WAY more important things to be worrying about than if you're going to avoid that PS'd laser. You're far better off just shooting regular lasers and keeping you're laser control and spacing and approaching on the right terms.
PS'ing is a great tactic to use against falco but it wont stop him, and the reason it wont stop him is not at all because of how you describe it.
Also, you're last paragraph is just dumb for more reasons than i care to describe. lol at standing lasers.