Cooper suspended for three weeks

Why did Bothma get a four week ban and Cooper a three week one for the same offence.  
I have also  have reservations about the one week ban of Sanchez for one of the worst offences I have seen for years. 
There is no uniformity  in this situation and some players gets away with murder.   Part of the blame should be laid  at the door of the referees that buggers up badly.

 Sanchez's knees to th face of Volmink(spelling) didnt even get a yellow the previous week. 
He had no eyes on the ball and zero hope of catching it. He all but knocked Volmink out. 
Anyone know if he's been cited? I haven't heard anything. If not though, it basically means that it had been reviewed with the full benefit of multiple camera angles in slow motion and deemed neither dangerous no reckless. How that is possible, I do not know.
Not sure how the rulings are made but one thinks that it shouldn't be too difficult to create prescribed penalties provided certain boxes are ticked. There are after all only about a handful of situations that represent the the vast majority of dangerous incidents. Namely tackles, high balls, mauls, players in the air and some others. 
A decent lawyer would make easy work of setting out fixed criteria. Right now it seems totally random. 

 plum
Was sited with the Citing Commissioner saying it was a red card offence,   That means he should have been red-carded - which he was not.
He got away with murder though - ie a one-week ban.

 So a slip up high tackle where there is no sign of intent is deemed 3 weeks. I saw Cooper's tackle and it would be impossibly hard and tenuous to prove intent.

But an even more dangerous situation where intent could shown is deemed 1 week.