YES PLEASE ! ! !
This is critical to my business too! Just like Netflix and Amazon, my subscription products change price too. Manual work around such as manual editing, or making clients re-purchase, is not acceptable.
As a side note, I had a chat with a ONTRAPORT CS rep just a couple weeks back on this same issue. They told me they would add it to the feature request list. Yet I now see they did NOT add my request! Makes me wonder how often the voice of paying customers are not captured in this forum.