All this is really the core problem that Moridens idea is exploiting, and I am dang glad he brought this up because it needs to be fixed in all these variations that people have posted here.
your welcome, i intentionally added as many borderline ruling's and horribly broken things as i could.
I guess the crux of the matter is how Catch and Stacked Catch actually work together. I would think personally that Physical Immunity is only decreased by the Stacked Catch and all your other powers are affected by the regular Catch. That's how I personally think they should work ... even though that's not borne out by a strict reading of the rules.
The wording is pretty vague, but the example pretty clearly shows that "currently" the implementation is that the stacked catch and base catch apply as kinda a "pool" of points that you can use to defray all of your toughness powers.
Now weather that can lower any individual power to -1 or if the "toughness package" can be lowered to -1 is the question.
example one you have 8 "points" from your stacked catch, and you take human form +1
you get immunity -8 and inhuman toughness -2
immunity -8 +7 = -1 inhuman toughness -2 + 1= -1 total cost 2 and a wasted bonus point from human form total cost -2
Example two same situation.
Your "toughness powers which all only apply in human form are a combined "combat form" and thus are effectively one big power.
immunity -8
Inhuman toughness -2
for a total of a -10 "power"
you then add your +9 from catch's and human form to bring it to a total of -1