I am really confused. I've read numerous posts that say that using Type-S mortar for shower bed is a no-no. I called Sakrete, and they confirmed that it's not for shower bases and more for laying brick, etc. Then I called Oatey to inquire what shower base should be made of to install their shower liner and the rep told me that I can use Type-S mortar. Who is right here?
Type S mortar is mixed really wet so it would be hard to shape it into any sloping shape and it better for thinner applications, like brick laying. If you mix it dryer that instructions say, you take the risk of it crumbling.
I'd be following the advice from the manufacturers of the mortar over the advice from the manufacturers of the products going on top of it.