Paying a reader to give you notes on your script is like paying a prostitute to give you notes on your sexual technique.
Yes, they're a professional.
Yes, they're good at what they do.
And yes, if you're just starting out there's a case to be made that advice from someone who's been around the blocks a few times is going to help.
But in the long term, both of them have a vested interest in continuing to receive your custom. And that means two things.
One: You're never going to be told you're that bad
Two: You're never going to be told you're that good.
To keep your custom, they have to always see that there's room for improvement, while also approving of your current skills and grasp of technique. Especially the techniques that they happen to like.
Now, if they're being paid by someone else to judge your work, then you can trust 'em - to a point at least.
They might not like redheads, or muscleboys, or people who dress to the left, but that's just life. If someone else is paying them to evaluate your performance and they don't like you, that's just incompatibility. Bad luck. And they can be as sharp as they like with their critique, because you never get to see it.
But if you're the one paying for the evaluation, they'd be a fool not to give you what you're asking for. Really asking for, which is recognition of the skills you've got, tips for improvement, and a haven't-you-done-well.
Whether you actually have any skills, or need any improvement.
In other words, you get what you pay for. Not necessarily what you need.