There are so many factors that impact the toxicity of noxious corals. Some of these would be, coral size, tank size, other coral species, and use of carbon (also how much carbon and how often it is changed), water change frequency etc.
As a rule it is best not to keep members of the Sinularia family with LPS or SPS corals. Most of the Sinularia family grow quite rapidly and become large, dominating the average tank in just a year or two. GSP's are another coral that is best left in a soft coral tank. Zoanthids and Corallimorpharians can also be problematic over time due to their stinging capability and prolific nature. When making physical contact with SPS they usually win and overtake the SPS coral unless action is taken by the aquarist.
HTH,
Kevin