Scaling not working properly

Hi everyone,

I am trying to make a barrel (learning how to use Blender) and I am in the part where I want to make ridges at two places in the center.

I have pressed Control R (Loop Cut) and then with the Bevel Tool I have created the ridge, but when I want to scale the ridge in the middle of the three loop cuts I have created it does not scale it proportionally. I have exagerated this in the picture so you can see it.

I tried already going to Object mode and the pressing Control + A and "Scale" before Scaling, but it does not work.

I tried also pressing Shift + Z before scaling and it did the same thing.

If I use Vertex Select instead of Edge select it works, but I would like to know why is it not working.

Can you please tell me what is it that I am doing wrong?

Thanks!