Nameserver records are specified in your zone file. The SOA record indicates the primary nameserver for the zone. There is no automatic relationship between the two. Here is a good read regarding SOA records. The short answer is that the SOA record is the whole record contianing the name, ttl, etc... Additionally, I'd strongly suggest picking up the O'Reilly DNS & Bind book. It's really quite useful.
Your records beyond the root servers for paulwarnk.com:
paulwarnk.com. 172800 IN NS adns.cs.siteprotect.com.
paulwarnk.com. 172800 IN NS bdns.cs.siteprotect.com.
;; Received 116 bytes from 18.104.22.168#53(M.GTLD-SERVERS.NET) in 152 ms
paulwarnk.com. 99999 IN A 22.214.171.124
paulwarnk.com. 99999 IN NS adns.cs.siteprotect.com.
paulwarnk.com. 99999 IN NS bdns.cs.siteprotect.com.
;; Received 100 bytes from 126.96.36.199#53(adns.cs.siteprotect.com) in 12 ms
Now, what this means is that, at the root servers, adns & bdns.cs.siteprotect.com are listed as the authorities for paulwarnk.com. Then, on those servers (adns & bdns) there is an A record for the root record pointing to 188.8.131.52.
I think what you're asking is why the NS records appear to be different. The answer is that the NS records were specified, likely by your registrar, to point to their servers that are authoritative for the zone. However, this output would seem to indicate a problem, as the SOA nameserver does not appear to respond to a request for your records:
; <<>> DiG 9.2.4 <<>> @a.dns.hostway.net paulwarnk.com
; (1 server found)
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 37849
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;paulwarnk.com. IN A
;; Query time: 10 msec
;; SERVER: 184.108.40.206#53(220.127.116.11)
;; WHEN: Mon Nov 16 23:03:04 2009
;; MSG SIZE rcvd: 31
The AUTHORITY: 0 means that the server a.dns.hostway.net did not answer authoritatively. It seems kinda obvious when the ANSWER: 0 section is there, but it's actually important to differentiate between an authoritative answer, and a non-authoritative one. Authority, in DNS, speaks to whether or not the server you've gotten your answer from can actually be trusted to know what it's talking about.
As to why there's a server listed in the SOA, I don't know that I've ever read the reason they put it there, but that server should be the master server for the zone, hence Start of Authority, or SOA. It's not always the case, as the SOA for all 1400+ of my domains lists a primary query server in the SOA, but the actual start of authority is on a hidden master that no one can access.