I agree - you gotta repeat the previous level when introducing the antes, or the jump is horrible and will take so many people from reasonably stacked to short stacked without touching a card.
Also, I note that the antes are almost always running at 1/8th of the SB.... looking at some other big tournies (was looking specifically at Aussie Millions) the SB wanders anywhere from 1/6th to 1/4th of the SB - this means the pot is so much juicier before the action starts, and obviously makes for much looser play and more steal attempts. Running antes at 1/8th of SB will decrease that steal value - an 8 seat table will only have equivalent of 1 SB added to the pot by antes..... which means not much difference between having antes and not having antes. IMO
Since making my original post I have given this more [some!] thought. I think that AMRN"s second point is actually more pertinent i.e. the small size of the ante as opposed to how it is introduced.
Because it so small, as little as 1/10th SB at some points, not repeating the previous level is not sooooo bad.
e.g.
WSOP structure - 100/200 [300] upto 25/100/200 [550] = 83% increase.
APAT structure - 150/300 [450] upto 25/200/400 [850] = 89% increase.
Still, no harm debating these issues, eh?
("Why is the Ante so low?" thread to follow!!)