Facebook Credits bought by Mobile Payments...Disclosure Needed or Not?

I decided it was time to check out Facebook Credits. Last nite I navigated my way to buying some not because I need any but just to see what the payments experience is. I was curious if they were surcharging their "friends" when paying with a Mobile payment instead of credit card. They are to the tune of roughly 50%. The consumer gets 1/2 the number of Facebook Credits when they pay by charging to their mobile phone number.

I realize that their merchant cost is high due to the carrier's fee and therefore it is not completely unreasonable to do this.

What I do find unreasonable is that there is no clear disclosure of what the deal is.
You have to click back and forth between the choices when wanting to pay with credit card and wanting to pay by Mobile and have to do the math in your head.

When I shop at the supermarket, I expect to be able to look at the labels on the shelves and see that the Coke Zero in the 12 oz bottle costs me $.05/ounce and $.04/ounce in the 20 oz bottle.

It is one thing for some low life elixer company to pull this sort of deception, but another for a company like Facebook that should care about their reputation and credibility. And it should not require the government or some other body to monitor and enforce reasonable and ethical behaviour.

The Mobile Marketing Association guidelines prohibit surcharging the consumer. But, no one is enforcing those. Of course, this reminds me of an earlier post about Visa rules being ignored right under Visa's nose; http://paymenttalk.blogspot.com/2008/05/rules-are-made-to-be-broken.html

What do you think?

BTW, I am going to dispute this transaction. I tried cancelling it afterwards following the instructions in the text by texting back "STOP" and even got a text seemingly confirming that the transaction had been "discontinued", but since the 16 credits I bought did not get taken from my Facebook Credits balance, I am presuming either this is a delayed process or simply does not work. I will call the mobile payments company first and see how they handle it. Then I guess I get to call Facebook and then if all else fails, AT&T. Stay tuned!