I think Comcast is offering that deal in many places, because they want customers to switch from analog to digital cable. Call your local Comcast office and check for sure.
I know a couple years back i was selling Comcast expanded basic for 49.99/mo (or $50/mo) and the digital version of it was only $1 or $2 more (between $50.99 and $52). It might be the same price now, either way, price difference should be minimal or none.
