I've use a lot of POR-15,but havent tried any bedliner coating over it--I know unless you put any topcoat of paint on while its still tacky,it will peel off like saran wrap.Seems POR-15 is pretty slippery when it dries,and many other paints dont adhere to it well.Maybe someone else can give a better answer who has tried it--I've put rubberized undercoating over it and it seems to stay on ok--maybe they have a website for POR-15 you could e-mail and ask them,or maybe a "Rhino Liner"place could answer your question--anyhow,even just the POR-15 alone will be pretty effective at converting and preventing more rust,especially on the inside of the truck where its hidden from the sun--U V rays degrades POR-15 and makes it go flat,but it still seems to work.