Asked support to provision my SB8200 with a second IPv6 network. As expected it was a waste of time. Got in touch with sales since there's nothing on my Philadelphia, Delaware county rate card for a second network. Should be around five dollars a month, was quoted sixty five. Anyone in the area have a Philly rate card with the second network option? Seems to be some serious shennanigans going on here beyond clueless support which is to be expected. It should be trivial to configure a second IPv6 network.
FWIW, it is being phased out so you may not be able to get it anymore in your local area. YMMV.