Lube plate for Trailair 5th. wheel pin?

When I purchased this current 5th wheel it came with lube plate. All of a sudden I'm having trouble hitching up because the pivoting head of my 5th wheel hitch not being positioned properly. I finally figured out that the square front end of my king pin box now has the rounded end of the lube plate sticking out. As I positon my king pin box 1/2 inch below the plate of the hitch as per proper hitching instructions, it now contacts the lube plate first, and a rounded edge does not cam or position the pivoting head. I would have someone hold the hitch level to the king pin box as I backed under it. Finally I removed the lube plate and I have no more problems hitching, even on non level sites. So word of caution about lube plates, you may not want to use it or if you do I would suggest trimming the front of it off so it's flat in the front.