I just read it up and well, it's up to Hyena...<br/>As in the Frieza Saga supplement it states if you want to sense what a Power Level is, then you need a PL of 20k+, make a Hard (18) mind+mental roll to know it can be done and thereafter you can automatically do it.<br/><br/>Thus most the aliens use Scouters for it.<br/><br/>Sensing Power Levels<em>in general</em>(so not knowing exactly how powerful they are) is also covered in the Frieza Saga supplement and you need a PL of 500+, same rules as above.<br/><br/>Hiding Power Level needs a personal PL of 300+ and again, same rules to know how to do so, then you can just do it, no roll needed.<br/><br/>I didn't know those PL limits in my prior posts, will wait on what Hyena says.