BT Line rental saver deal

I'n hoping to do away with the landline someday, having to keep it for now for the internet. In the meantime I have been looking around to see the best deal for rental and calls. It's difficult to manouvre the deals. For now, I have signed up for the BT Line rental saver deal.

BT line rental saver deal : what it entails
This is my understanding ...
You need to pay a year in advance
Currently it's £10 a month, but soon is going up (£10.28 ?)
That's £120 a year
You need to use BT for 2 calls a month to stay qualified
Calls look around 13p connection and 8p a minute local ? (basic package)
Free at weekend (same as basic package)
Direct debit needs to be set for the phone bills 

I plan to use make sure I do the 2 calls a months using BT then do all other calls through 18185.

So this will do me for the next year until hopefully mobile unlimited internet gets underway.