Observe now 7 CP??!!

[Silverbane]

over 10 steps it will average -2 CP, over 20 steps it will average +16 because over 20 steps, that would 5 procs at 25%. So yes, we can very likely do indefinitely.

Unless I missed a change in the Patch Notes, the odds of a G/E proc are not 25%. It's more like 9% (L60 2-star) or 14% (L58) depending on the level of the recipe.
See http://forum.square-enix.com/ffxiv/t...ar-L60-recipes

So on average you'd get one ToT doing CZ+10xObs on an L60 2-star craft. If lucky, two.

In the former case, your spent net CP is 66(Cz) + 9x7 (9xObs) + 10x-8 (CZ rebates) + 1x-20 (ToTs) = 66+63-80-20 = 29 CP.

In the latter case, your spent net CP is 66(Cz) + 8x7 (8xObs) + 10x-8 (CZ rebates) + 2x-20 (ToTs) = 66+56-80-40 = 2 CP.

Not something you can maintain forever. But still, this change makes Observe useful, for the first time.