The GM, Eric, decided that since 'size tiny' was the same as taking the 'permanent' flaw with the 'shrinking' power, I had to take the additional penalties listed under the 'shrinking' power but not on the size table from the stats section -- namely, an 8 point penalty to strength and -10 move.
But 'size tiny' from the table didn't seem to cost the right amount for that -- with the permanent flaw it should have cost half as much, while it was listed at full strength. Since the enhanced sizes (large, huge, etc) *did* have a discount, I figured it must have the 'normal strength' extra counteracting the 'permanent' flaw.
"Oh no," Eric said, "To buy permanent you have to first buy the duration up from 'sustained'" (which means 'active as long as you want it to be with no concentration required') "to 'continuous'" (which means, 'active until you explicitly deactivate it, even if you go unconscious', and is the default duration for powers that it doesn't make sense to even turn off in the first place, like enhanced senses) "which cancels it out. The larger sizes are cheaper because the cost for the growth power is wrong, and it must really cost 3/level since both that table and the index have it listed as 3/level, while only the one place -- the actual power description -- has it at 4."
I thought this was really stupid, and that obviously 'permanent' was meant to be able to be applied to 'sustained' as well as 'continuous' powers, but he's the GM, and that's really a judgment call unless the author specifically mentioned it somewhere.
But... wait a minute... there's no point break for being permanently tiny, as opposed to being able to become tiny as a free action whenever I want? The solution is obvious -- I changed the character to a size-changing cat, then applied two copies of the 'action' flaw so that it would take a standard action to change sizes... not something I ever intend to do anyway. For the hell of it, I made the power continuous, subtle, and innate, so that my background could be that the tiny size was my normal size but I could get big if I wanted (since continuous means it won't switch off even if I died, subtle means no one can tell I have it running, and innate means it can't be drained or negated). Total cost: 7 points, instead of 8.
Eric was fine with that.
I didn't: Use *three* copies of 'action' to make the character miniscule for 5 points, buy his strength down to 1 at normal size (since the reduction in strength per level of shrinking is 'to a minimum of 1'), end up having to spend no points on attack or defense to cap them both just with size modifiers, then buy 34 points worth of shadow-summoning, darkness control, and other crap with the points saved.
I threatened to, though, and it was clearly legal. Maybe that's why he was okay with the version I went with.