No, they will first, test the VLT compliance visually first, aka tengok pakai mata jer. If that one tak lepas, then, they will take out the equipment and measure it. Sometime, if u unlucky, they don't bring the equipment, then, they will give u memo ask u drive to JPJ office for them to test, where they got equipment. Some shop, they even got the equipment, so, after tint, u can measure on the spot oso.

If u tell the shop u want strictly JPJ compliant tint, they will tell u which one, and that one, if u kena saman, u bring the saman to the shop, they kaotim for u.  Whether it is dark enuff for u or not, lain cerita lah......

If front screen is 70 light comes in so you're fine
Or huper optik 60/40/40 arrangement, cover saman

u go those big brand shop HQ, usually got....apa brand u targeting? 

the one thing i always wonder is, how true is that 75% or 85% or whatever % they are saying? As a consumer we dont have a tool and device to actually measure it for ourself and we get exploited.

Unless there is some device to actually verify it would be handy and not by just feeling the IR for few sec when they demo the tint to us.