The added ringtone step is supposed to be a reply yes from the handset instead of a PIN submit.
Any change will affect everyone the same. So if conversions go down 30% you can rest assured the cost to get traffic will go down the same.
Ringtones are just another hot offer of the time, it used to be credit cards, then nextcard went belly up, then it was debt consolidation and mortgages until the FTC stepped in and cleaned house, now its ringtones. As with any new industry its a bit of a wild west until legislation comes through to guide marketers on whats acceptable and what is not. once legislation sweeps through, the market looses its lucrative characteristics and those who are big in it, need to find something new or die off.
The lesson is to find markets that are stable and not as volatile as ringtones, I am a big supporter of online dating as its been a top 5 industry online for the last 5 years and shows no signs of slowing down. However if volatility and sweeping changes are something you can deal with then continue to promote ringtones.