As far as I can tell, the cost of the SSL endpoint on Heroku is almost exactly the same as the cost of a separate Elastic Load balancer, which you need to terminate the SSL connection before it reaches your app. So Heroku is really just selling this feature at cost.
I don't remember additional charge for using SSL with ELB (but ELB is extremely dumb so if you want to apply fancy headers and rules, ELB is out of question, either roll out Nginx or HAProxy with ELB governing failover. Direct R53 failover only works with public zone).
