Slow Custom Domain on GAE

I recently deployed an application to Google App Engine (GAE). Accessing the application via the appspot.com subdomain was fast however the custom domain consistently was slower (sometimes 5 seconds versus 200ms). I believe the issue is that custom domain was set up on the same day and that the DNS has not propagated through the internet completely. This leads to some crazy routing to Google's network.

I'll wait a while longer because I ask the Google App Engine group (not much else other than this explanation is mentioned in the searches I've done). I'm going to reboot my local wireless/wired routers.