I'd be REALLLY surprised if the plates you are referring to are of the same quality as these. These are 3/16 thick. I know there are inferior ones out there, at lower prices, but lets face it! YOU GET WHAT YOU PAY FOR! And these are exceptional pieces! I'd be curious as to which plates you are referring to.
Here's the link... http://mauromotorsports.com/raskpln.html
That's why I asked you the thickness. These guys may only be 1/8", but that's still pretty thick and also possibly lighter. It looks to be the same size as far as coverage goes...What is the weight of your plate?