You're confusing "Nomination" with "Appointment". There will be a lot of people with nominations who don't get appointments. Matter of fact; more people applying will have nominations than who actually get an appointment. Here's the 2 ways your congressman's nomination works.
1. Each congressman provides a slate of up to 10 names. These 10 people ALL have nominations. That congressman might RANK those 10 names. If they do rank them; then the #1 person on that list is considered the "Primary" nominee, and for all intent and purpose, is guaranteed an "Appointment". Assuming of course that all other aspects of their application passes at least the minimum. And it doesn't matter what their WCS is from the academy. As long as it's at least the minimum required.
2. Same as above, except the congressman doesn't rank the nominees. The difference here is that all 10 of these individuals will then go into the "pool" that you are referring to. HOWEVER; it isn't as simple as saying that those with the highest WCS get an appointment. That isn't allowed. If it were, then theoretically all 1300+/- appointments could come say from California because those applicants happened to score the highest. The WCS will matter, but each congressman is allowed "X" amount of individuals from their state/district to get an appointment. (The "X" changes depending on how many are currently at the academy as current cadets). Now; once the academy has given the appropriate appointments to those from that State/District from the slates given to them by the state's congressman, then the REMAINING APPLICANTS will go into the National Pool that you are referring to.
Now, back to your situation. Your friend could have gotten called from the congressman, and you didn't, for a number of reasons.
1. That congressman ranks their slate, and your friend is their #1 slot, and they notified him. That doesn't mean you didn't get a nomination, just that you weren't #1 on their RANKED slate. As such, if you did get a nomination, but not the #1, you will still go into the national pool.
2. That congressman might contact all 10 people that they gave nominations to, and your friend was one of those 10. And you might not be one of the 10, so they didn't give you a nomination. (Worse scenario).
3. This is really a 2a, but many congressman talk to each other. It's possible that they don't want to nominate a person if another nominator is nominating that person. This way the they can get in as many as possible. You could be getting a nomination from one of your senators, and your representative didn't want to nominate you also.
Remember however that the national pool you speak of doesn't do anyone any good if they don't have a nomination. Your congressman did NOT give out just 1 nomination and tell the others too bad. S/He probably gave 10 nominations. 1 might have been a primary (AUTOMATIC APPOINTMENT), and the other 9 people are in the national pool. Basically, there are 3 people you can get a nomination from. Your representative, and your 2 senators. The senators can nominate 10 each among ANYONE in the state. Your representative can nominate 10 on their slate, but ONLY from your district. If you're one of the 10, then you have a nomination; and have a chance of getting an appointment. If you aren't one of the 10 on one of those 3 lists, then you don't have a nomination. And without a nomination, you can't get an appointment. Of course, there are other sources for nominations, such as presidential, vice presidential, ROTC, as well as the academy itself having some slots. As well as some other nomination slots.
So don't give up all hope yet. And I hope I explained the process better to you. All 10 on the slate receive nominations. But that's why more people with nominations WON'T get an appointment to the academy than those who do get an appointment. Best of luck to you. mike....