Bundling with BellSouth

I am currently a Bellsouth telephone customer but I have my cable and internet through Comcast. The total cost is $142.71 per month for telephone, cable, and internet. I am also considering keeping my Comcast cable but dropping the internet for Bellsouth DSL. I need to do the math and see what makes the most sense. I think I could get a BellSouth bundle for about $120 plus I could get $225 cash back. Even if I only save $15 per month it would add up to $180 over twelve months puls there is the $225 cash back to consider. My only hesitation is that having everything installed would be a pain.