I agree with achieman.
Programs only expect/require 3 (unless the inform you that they require additional letters). More are not necessarily better in this case i.e. the dilution of 3 great letters with an additional letter that is not as strong as the first 3 and is not required.
I mentioned this in a previous post, but I would give your letter writers a self addressed stamped envelope in addition to a stamped envelope addressed to your student affairs' (or whoever does your match stuff) office. Your letter writers will know what to do with the envelopes. If they want to send you a copy they will.
All of my letter writers ended up sending me a copy. That way I was able to choose the best 3 letters to choose.
Good luck.