Thermostat probe question

So i don't know if its just me, but every time i think i understand the right way to do this, i read something that confuses me again. So the probe for my thermostat goes in the center of my heating pad BETWEEN the heating pad and the bottom of the tank. right? so

bottom of the tank.
probe.
heating pad.

right?

That is ideal, however "store bought" UTHs like from Zoomed or the sorts can become damaged if they are bent even the slightest. If you are using one of those, I suggest putting the probe under the UTH. So:

tank
UTH
probe

Still in the center and be sure it's secure. That's really the only time I'd suggest putting it under the UTH. Once those are damaged, they can short, or cause uneven heat spots.