[HTC Amaze 4G] AndroidAutobot:
That wouldn't be the first time there was something on T-Mobile.com that was tragically outdated Intel wise. I'd be extremely careful about representing yourself as a t mobile employee on forums. It sucks, i know, but it is a pretty serious offense. There was a time several years ago where all I was doing was helping some customers out on T-Mobile support forums and they suspendednmy account for presenting myself as a t mobile representative. Acknowledging yourself as being an employee of t mobile is a gray area. I think they're more sensitive about circumstances such as this (that I was guilty of before I was aware) where you say "I work for t mobile and let me tell you..." Etc etc.

I would give you the link if I could, but (not trying to argue, only educate) what you posted is true of OLD WiFi calling features, yes. there was a change (sometime a little less than a year ago I think) that occurred that once again provided free minutes over WiFi, which is still in effect today.

As far as being billed for calls over WiFi (now addressing the op and everyone in general) - its not possible, at least not on the Amaze at any rate. If you dont have the feature, you're not actually making any calls over WiFi at all. There are two types - those that have the feature built into the settings of their phone (this is the case with the amaze) and those that require an additional WiFi calling app that t mobile included on certain models.

It is possible to be billed minutes for calls over WiFi for the latter of the two.

With the amaze and most other new models (the ones that have the feature built into their settings itself), provided that the feature is enabled (on ICS its settings > more > WiFi calling and WiFi calling settings) it automatically connects to the network and gives you a blue or red notification depending on if it was able to connect to the network over WiFi. If you dont have the feature, it won't connect and there's a very obvious red notification that appears informing you of sich. I'm thus a bit surprised that you were under the impression that you were making WiFi calls and hadn't noticed that notification.

The feature itself is more of a provisioning feature than anything. If its applied and you have a compatible simcard... It will work and you'll have a blue notification. If you don't have the feature, the system rejects the connection over WiFi, you get a red notification and your voice services continue to be connected over the network. While your data itself is all that's connected to WiFi. If this feature isn't offerred to you when you activate or buy your new phone, the rep is probably pressed for time (hustle and bustle makes it hard to remember every last detail sometimes), neglectful, or lacks the knowledge necessary to properly present the service. Everyone is human guys, give your reps the benefit of the doubt. No one is out to get you. From my experience, most of t mobile's workforce is full of genuine, honest people who believe in the company they work for. T mobile tends to attract people with a much higher caliber of values since the company's operations in general tend to be much more customer advocate based than other cell phone companies. I've actually known more than a few people in the industry who want to work for t mobile more than any other company and who have stayed with t mobile when other more lucrative opportunities have presented themselves because of T Mobile's high standard for recognizing their customers as people and not another metric to be achieved.