IEEE page charges for Open Access

I just got an email saying my page proofs are ready for my paper with Alex Dimakis on mobility in gossip algorithms. If I want to make the paper open access, I have to shell out $3000. I think this is in addition to the $110 per page “voluntary” page charges. Now, I’m on the record as being a fan of Open Access, but $3k is a pretty hefty chunk of change! Has anyone else had experience with this?