He's actually right. You may feel a slight coars surface when you move/slide your palm on the wet/slippery surface of your car. I only figured it out when my 800 gsm microfiber towel literally got stuck to the surface jaisay chotay chotay kaantoun Mei phans Gaya ho - if you know what I mean. Anyways, it is always good to strip wash, decon, wash again, seal/wax and you'll have a sleek smooth protected surface.
Also, you probably will see the orange peel on your surface since imc does a shit job when spraying clear. I can't stand it on my car but don't have the time or energy to wet sand the peel out and polish the entire car.