It can be true, it just means it has time release nutrients ( more than likely). Those soils can be really hot so be careful using it.
I agree with @gregthe357 ... If you do end up trying it, you may want to use a TDS tester and do runoff checks to ensure the nutrients are there as well.
@Mr. Grow It thank you. The super soil says it has everything it needs. I can tell you it smells like a corpse in 100 degree weather lol. It says to mix it in the bottom of soil then soil on top. I will see how it