Considering on my main class I can kill the SSS O4s Dummy with 12 seconds remaining, and still have 1% on the shinryu ex dummy when time runs out, Shinryu Ex seems to require MORE dps than O4s.
*shrug* I don't bother with SSS dummies, they're pretty inaccurate representations of how actual fights with actual mechanics go anyway. Test your rotations and your DPS on them if you want, sure, but they're not really helpful for determining how well you'd be able to both handle a fight's mechanics + still contribute the expected level of DPS despite those mechanics... since there's no mechanics.

Even something as simple as a mob turning around to use an attack on one of your healers can considered a DPS-hampering mechanic, as if you don't expect it coming you can whiff a positional because of it. That's a sort of thing that will only come with fight knowledge and practice, not dummies.