where does it say that SS cannot be PCed at all? Or is that rule just a venue specific jargon?

It isn't that it can't be PC'd at all (though I suppose some may house rule it as such), but the timing of PC makes it very difficult to pull off.

From the PAC:

PROBABILITY CONTROL (OPTIONAL): Once during your turn, this character allows you to reroll one of your dice (or die) rolls and to ignore the result of the original roll. All dice used in the original roll must be rerolled. A character using this power must be within 10 squares of the character for which the original roll was made, and have a clear line of fire to that character. A character can use this power on itself. Using the same rules, once during an opponent’s turn, this character allows you to force that opponent to reroll one of his or her dice (or die) rolls and to ignore the result of the original roll. In games with three or more players, this power can be used only once between your turns.

As you can see, you can reroll your rolls on your turn and your opponent's rolls on your opponent's turn. Now most of the time, you roll Super Senses on your opponent's turn (since your opponent would be attacking you); since it is his/her turn, you can't PC your own rolls. Now, if for some reason your Super Senses are triggered on your own turn (maybe you are playing against Scenario Galactus and he's retaliating), then you could use PC on Super Senses.

Same thing goes for your opponent's Super Senses rolls (his rolls, your turn) and Impervious and Shape Change.

You can use Probability Control on your rolls when it's your turn and use can use probability control on your opponents rolls when it's their turn . Since it's your turn when you attack your opponents character with Super Sences , you can't use probability on his SS roll becauce even though he's rolling it's still your turn .