AT&T's new Mobile Share plans are misleading in that they are basically a limited promotion on par with how cable companies offer you an introductory rate, which is then increased at a later date. 

I'll start out by saying AT&T's new 10GB Mobile Share plans are a good deal: four lines, 10GB of data at $160. You arrive at that amount by adding 4 lines at the new reduced rate of $15 per line (4 X $15 = $60), regardless of device, plus $100 for that 10GB bucket of data. 

And that's exactly what I got. 

However, a day after having switched to that plan on February 3, I upgraded one of my lines to a new iPhone 5C. When I checked my bill, I found that the monthly per-line fee for that line had increased from $15 to $40. 

When I called customer service, I was told that the new plans were only good for existing customers on plans active on or before February 2. Upgrading to a new device is essentially initiating a new plan/contract, which means that any time I upgrade a line, I'm going right back to that $40 per-line monthly connection fee. For a plan with 5 lines, that will eventually mean an extra $125 per month if I upgrade. Which means my $160 plan eventually increases to $285 per month.  

Covering this industry on a daily basis, I'll admit that I should have known better. There's no way to get around device subsidies. Sure, with this offer, AT&T was partially doing away with a portion of some subsidies, and new customers switching from another carrier can also get this deal. But that's just a temporary discount, in part I'm guessing to deflect T-Mobile's agressive strategy, and not something AT&T can maintain. 

What's irksome here is that AT&T hasn't actually changed its pricing structure, rather it's conveniently playing down facts in its messaging that are important to customers. When I upgraded that line, no one, and I mean no one, told me that I would be paying a $40 connection fee for that line. 

When I look at the front page of AT&T's website, I see the embedded advertisement, which makes it seems like a straight-forward, 4-line, 10GB, $160 family plan is a real option. It's not. It's a limited-time promotion, unless you intend to keep the same device for the rest of your life, or you want to finance your device through AT&T's Next program.  

The thing is, I probably should have known better, but people not as well-acquainted with the industry are being strung along on this one. In looking at one of AT&T's forums on this topic, I am not the only one confused by exactly how this plan works. 

To be fair, AT&T did make it right with me. Because I'd upgraded only a day after February 2, the customer service agent changed the date of my upgrade and in turn, got me the $15 rate on that line. 

If you're confused by any of this, I don't blame you. As this price war continues, with Verizon now in the mix, the carriers are depending on confusion as a way of keeping the water murky. Subsidies have made American consumers ignorant of what it is they're actually paying for when they sign a wireless contract, and carriers intend to continue leveraging their confusion in an effort to make a big bill look like a steal.