Sorry guys - I feel like I'm permenantly looking for answers!
DS - 11 days - has started posseting a fair amount with every feed. It seems to happen well after he has finished. He's also started 'aggressively' eating and pulling off the nipple fast - and then wanting more Fast.
Perhaps he is just eager and then the let down is a shock so it comes quicker than expected, he is still learning after all. You could have his positioning checked in case he is taking in air with the feed and that is causing him to posset. Wouldn't worry about the amount in itself.