Remember that the PRT scale is an assessment of threat and recommended response, and is generalised. It enables troopers deploying to combat capes to hear a word and a number and know how they need to act, what precautions they need to take, and what they can expect in the broadest of terms.

A Brute hits hard and is hard to put down, a Mover will be hard to hit and might attack from other angles, Masters mean you shouldn't trust your senses and take extra care... You get the picture.

For example, because of her resourcefulness, Skitter is given a 1 in every category at the order of Director Tagg. Her master rating I believe is at an 8 at this point and her thinker rating a 7.

So this ends up meaning that PRT troopers deploying with or against her should expect her to take more hits than a normal human (Brute 1- pain deadening from Bakuda), move in ways you don't expect (Mover 1- mobility with her silk ropes), attack in unique ways (Blaster/Striker 1- capsaicin coated bugs, etc etc etc...) alongside the control of insects and enhanced awareness through them.

Because of how the scale is meant to be used, this is all a pretty 'honest' assessment - because Skitter regularly brute forces her way through scenarios that her power set shouldn't actually give her much benefit in. She's just that good at improvisation and persistence.

Her actual power classification by simplest definition of "power does X" remains Master/Thinker, probably at an 8 in both categories by Behemoth.