Correct, the example I gave is a solvency turn. Personally, I very rarely run harms turns (i.e., HR abuses are good, etc), just because they're usually really difficult to get judges to buy. Obvious exceptions are hegemony, democracy, globalism, (sometimes) global warming, etc. A "solvency turn" functions more as "you make your own harms worse," which I guess is still a turn on harms. However, I find it easier to have judges flow it on solvency just because that makes it clearer how your card interacts with solvency. Also it makes it so the aff can't just extend solvency and cross-apply it; it makes your turn a very clear answer to solvency proper.
Fantastic analysis of the solvency turns. Although there are some cases that it doesn't apply--inherency can function as uniqueness for the turn, if you're going to collapse to a solvency turn, there should be some mitigation on the harm. In your example, "The economic collapse won't happen because X, Y, and Z, but the aff causes it to happen via my turn."
For an example of when uniqueness isn't a huge deal, a debater from Western Kentucky is running an aff with a 3-card biochar advantage. The A card is that biochar is underused/not used at all (I forget which), the solvency is her plan allows widespread use of biochar. We have a turn that, in one card, says biochar would lead to extinction of all humans. In that case, uniqueness doesn't matter for the same reason it doesn't matter on the harms debate--the aff has already supplied it, in this case with inherency.
@LofB: Mostly in agreement, with two minor exceptions... I contend that ALL elements of a DA can be found in a single card (if it's awesome), and that if it is a new issue (e.g. "your case guts the NPT" but AFF advantages and harms never mentioned NPT) it would at that point not be a "turn".
1. Yes, they can be found in one card. That is, however very rare and in 7 years of debate I've only seen it like twice. But yes, if you find that awesome of a card, you could have a one-card DA. We have such a card for biochar in our files right now.
2. Again, you're right, that wouldn't be a turn. This applies more to college than NCFCA, but I wouldn't signpost it as an off-case, simply because judges get cranky when non-novices waste a sheet of paper on one card. I would probably find the part of the aff that guts the NDT (plan text, solvency, something must give you the link), put the DA there, and call it a turn. That's more stylistic than anything, though.