[MA] Push and Push Kick differences?

[Ultraviolet]

Unless I misread the Push Kick technique from MA, these two attacks do the same 'damage'; Thr x2 (for knockback purposes only). This seems the ok damage, since kicks are straight thrust, right?
Alternatively I misremember the 'ordinary' Push, which should be thr-1, like most punches. Although this isn't a punch, but a two-handed attack, or what? Is there any difference whether you push with one or two hands?

Or should the Push Kick somehow be based on ST+2, like most leg-techniques use +2 ST but -2 DX?

And would a Push get bonus damage from Sumo (only), while a Push Kick from either Brawling or Karate?

Note, there seems to be some slight difference in the two attacks, where a Push Kick aimed at a leg, confers a -2 DX for the foe to keep standing up.

Last question: Has anybody had any luck with a Push in actual play? My ST 12, Sumo at DX+1 guy failed to cause any knockback the times he tried...bad luck perhaps?