ThinkOrSwim quoting - what exchanges and how handled

[Risk619]

I've been poking around more in multiple exchanges and ECNs, and am seeing the fairly large spread that can exist between them. I'll see roughly 12 exchanges or ECNs issuing quotes from the IQFeed.

Does ThinkOrSwim source from the public exchanges and ECNs, and then just report in the last trade from whichever is more recent? Like if the last trade on Nasdaq for XYZ was 100.13, and 50 shared were sold on the Boston Stock Exchange for 100.10, would ThinkOrSwim display 100.10? Is it aggregating the activity from all exchanges, since it does "smart" routing on the execution side?

I tried looking this up on ThinkOrSwim and found this link, which doesn't really answer the question as to how their quotes are structured.

Does thinkorswim deliver real time quotes?
Yes, thinkorswim by TD Ameritrade does deliver real-time quotes as well as risk analysis and P/L. There is no fee for Non-Professional users with funded accounts in excess of $3,500. However, there is a $200/month fee for Professional users to obtain real-time quotes. The exchanges classify any licensed individual (Series 3, 7, 63, etc.) or an individual trading in an entity account (LLC, Partnership, Corporate) as a Professional.

What exchanges or ECNs does thinkorswim route to?
In the case of listed stock execution, thinkorswim routes to the NYSE SuperDot system. NASDAQ orders will be routed to the one of eight different ECNs that has the best market, and option trades are routed to the exchange with the best market. The option exchanges are: AMEX, CBOE, PHLX, PCX and ISE.