Re: Does it take into account
I also doubt it takes into account those of us who can be bothered to do the retentions dance, I've never had a problem calling EE, telling them about a deal through Carphone warehouse on their, or even another, network and them matching it via a line rental discount, takes 20 minutes maximum if you're polite about it.
They're usually happy to carry over a previous discount as well, meaning my line rental actually ends up cheaper than the offer I'm giving them as an example.