Ok, that works if you are thinking of getting a cellphone vs. not getting a cellphone.
But when you are thinking of getting what type of cellphone, no, it doesn't count. Cause by deciding you are getting a cellphone but trying to decide which type, you already committed to buying the plan,what type of cellphone does not affect the cost of the plan, you are going to pay it regardless. So the cost of the plan really doesn't count for the cost of the cellphone when you are comparing cellphones together.
Maybe if we were comparing getting a landline to a cellphone (where the costs of the service for the landline are going to be drastically different).
Or even if we were comparing going from AT&T to Verizon there might be some small difference. So only if the cellphones are on different networks (with the iphone though, this only matters if you are comparing to a T-Mobile or Sprint phone as you can get an iphone on either AT&T or Verizon so the plan cost will be the same for the iphone as whatever other phone you want to get on either network).
You still don't get the point.
The point is when we are comparing different cellphones to each other, the service doesn't matter cause if you are getting the cellphone, you are going to pay the service regardless and which cellphone you get isn't going to affect the service's price. Therefore it is irrelevant when talking cost of one cellphone vs. another to bring in the cost o the contract.