Well theses forums are a wealth of information.

I am sure you will find your answer in it somewhere.

For example with BTC (AUTO) and X11 you are getting a payout from profitable X11 coins to BTC.

When those coins are in a pump and their prices are good against BTC, then you get more BTC each day and when their not doing so well or are being dumped then you get less BTC each day.

If you are mining those coins directly then when mining, payouts will always vary every day based on difficulty of those coins and the network hashrate at the time.

So read up about those things so you can understand why payouts are how they are.