My experiece with Rynga and its FUP

We've been using Rynga since last Dec. and its overall sound quality is very good. It also gives you 120-day free calls after each recharge. We basically calling China 100+ minutes a day, and never paid per-minutes charge. There is an 5-cent(euro?) connection charge for each call. About FUP, we've just learned that if you calling out a lot in a short period of time, then the FUP charge will be triggered, with is about 1 euro cent per minute. However, not sure about how soon you can make another call for free.

Just my 2-cents.