I have no clue what this stuff is but someone mentioned about being like por15. Well there are chemical companies that will give you the formula to make a por like product or have it made for you and put your label on it.
The product is cheap to make and easy so I would guess there are a lot of copies out there.
With this in mind I would not do anything with anything over the product you are using until you talk with the company.
If it is a copy of por then you will need what they call tie coat before applying anything over that product so it does not peel down the road.
Your pretty deep into the job at this point to be short cutting or screwing up so I would call.