Total bounty is confirmed + unconfirmed. Total bounty in 24h can be higher if you received a payment (i.e. the part that was paid is no longer in confirmed or unconfirmed)
Right, like I said though I have payout set to 1 BTC and received no payments during this period.
Well, you didn't actually say you hadn't received a payment. And, to be honest, I would have expected you to have received a payment in the past 24 hours as you're generating about 1BTC per day. The mine was also down for part of yesterday so that could have something to do with it.