I can see both angles on this. The average consumer isn't concerned about
how the amount he is paying is going to be apportioned, he just wants to know what the bottom line will be without having to carry out a lot of mental arithmetic. Hmm.... $5 flat service fee, a 2% local tax, a 3% federal tax and..... Hold on a moment, is that 3% tax added to the total or to the amount
before the service fee? Do I include the 2% local tax in calculating that?
And so on.
On the other hand, when it comes to something like the telephone bills I can understand the phone company wanting to put across a certain message -- Hey, we're not ripping you off for 50 bucks a month, we only get $30 and the rest is all these taxes and fees. When the mandatory taxes form a substantial part of the total I can understand that. (Imagine if the receipt you got from a British filling station said "Fuel £10, tax £30." It might wake a few people up!)
I can see the extension of this to something like an airport car rental place where they have to pay the airport an additional fee per car and want to make it clear that the extra money is not simply an attempt to fleece people at the airport by charging more than at other locations, but a genuine extra cost incurred by doing business there.
I agree though that some companies just use service charges and the like as an excuse to complicate the situation so that a lot of people don't realize how much they'll end up paying in total and so that they can advertise a low "sticker" price which attracts attention, then it's only when you check the small print you see the "Plus a 5% service fee for all transactions below $500 dollars," or whatever. There's definitely a certain amount of smoke and mirrors effect here.