I too was on Ultra. I didn't take any chances and requested I be placed on BLAST, which is technically a sideways move with Blast replacing Ultra. It took me three calls before getting it done without them wanting to add an additional $10 onto my bill.
I wound up paying the rate increased price of $74.95 (Stand Alone HSI) as opposed to $72.95 I was paying but 2 days later they upgraded to 50/10 so Im happy.
If you own your own modem be sure to verify that stays the same and make sure a tech isn't scheduled to come put as well .. both of those things changed over the 3 calls. Apparently modem rental and techs are part of the Blast tier --
Yes, I Will Fix Your #@$!! Computer