Have a look at
http://www.pprune.org/tech-log/36574...-ops-a320.html where its been discussed previously.Ive had to shut down a pack very early into a 5 hrs 30 sector where I could have continued below FL 315 where a tech stop was probable.We elected to continue at higher levels with single pack ops but after landing the CIDS started to give some problems due to the fact we had 180 pax on board and a lot of condensation had built up behind them!!