Penalty runs

I've long suspected that much we hear on the radio, in particular, and on television about overrunning because of slow over rates is mostly about commentators wanting to get away to the pub but I do agree that the speed with which Tweny20 matches are played is much better than the dawdle you often see elsewhere (even in club cricket). And this is much to do with the penalty runs system.

However I watched two games last week one at The Oval and once on TV where the sudden change in the target changed the whole match. At The Oval Surrey's target changed from 14 to 8 off the last over (big difference, although they still failed to get there). Fair enough to penalise the players but tough on the supporters - is there not a better way?