It depends.
For the lurkers, a Senator's nom does not count more to the SA than a House of Representatives nom, and a Representative's nom does not count more to the SA than a Senator's nom. A nom is a nom is a nom. Be glad and grateful if you receive a nom. It is usually the first "cut" that occurs.
There is already a good thread here on Multiple Noms:
http://www.serviceacademyforums.com...ations-to-a-single-academy.45011/#post-460106
If you are the #1 on a MOC slate (Senator or Representative), and you are 3Q qualified as determined by the SA, you receive the appointment unless there are very rare and unusual circumstances.
If you aren't #1 on a slate, you go on the NWL/in the National Pool.
I believe the inference from Coach62 and brovol is that a candidate has a better chance being #1 on their House of Representatives slate as opposed to their Senator's slate. That could be, but it really depends on the competitiveness of the applicants in the state, the competitiveness of the congressional districts in play, and how much the Senators and Representatives coordinate their picks.
For instance, in years past, the Virginia senators and representatives (especially from the very competitive districts of VA 10 and VA 11) would coordinate so they didn't duplicate nominations in order to maximize the opportunities for the large number of deserving applicants. I've been told by their review board staff they would even share their selection/ranking lists with each other prior to making their noms known, and then they would re-allocate kids from the competitive districts to the Senators in order to maximize the opportunity for the most qualified candidates. It is common in VA for there to be 200-300 applications for a nomination to each SA to each Senator and to the VA 11 and VA 10 Representatives. The applications are all from separate distinct kids because in VA you can't apply to multiple SAs with the Senators and the NoVa Reps. You have to pick only one. The MOCs then seem to select around 50-60 of the nom applicants for interviews and then, as you know, 10 get a nomination. So let's say VA 11 had 15+ kids that deserved a nomination and so did VA 10, and then there are the other 9 districts of the state of Virginia that had deserving candidates but not as many as in VA 10 and VA 11. The Senator and Reps review board chair, in years past, would try to coordinate so each of the 15+ from VA #10 and the 15+ from VA #11 would get a nom either from a Senator or their MOC -- and they didn't just give "the bottom 10" from the MOC to the Senator -- so it might be that the #2 kid on VA10's list becomes the #1 kid on Senator X's slate, and the #2 kid on VA11's slate becomes the #1 kid on Senator Y's slate. They would coordinate and allocate and in effect "disperse the talent".
Hope this makes some sense . . . you can drive yourself crazy trying to game it . . . for those getting ready to enter the process the best advice is to work hard to make your record of academics, leadership, athletics, community service, etc. as good as you can. Apply for a national ROTC scholarship as well, and work on having a great Plan B that will get you a great education and prepare you to serve.