Yup, he is correct. That is a better solution.

What you do is move the the point where the linkages connect to the servo horn "in" towards the servo horn screw, and then the linkage at the control surface "out".

You can do this a hole or two at a time.

As you move the servo linkage side in and the other out, you increase the lever moment of the servo, increasing force.

As you'll recall from high school physics, you are adjusting the fulcrum.

At the same time this reduces the amount of control surface travel.

Typically I will turn the TX's travel rates UP as high as possible then make these adjustments so that I get the movement I desire from the control surface.

In your case the servo is trying to push the control surface futher than it will move, causing the binding you are experiencing.

With the above you are effectively reducing the total travel amount and at the same time gaining more torque, which will help prevent flutter and give you more precise TX control.

Remember that ideally at ANY stick extreme on the TX, your servos should move to the extreme, then go quiet, having reached the commanded position.

If they are not able to get there, you get buzz.