What I do is just use stratehm.net and get the difference of total(balance+unexchanged+immature) balance from the beginning of a day to the end and divide by total hashing power of middlecoin for that period.. and viola you have the current BTC/MH/Day with all unexchanged and immature taken into account.
So what do you do when stratehm.net is down? Well, at least it's down for me. I suppose I shouldn't speak for the entire Internet.
Based on the data I scrape from Middlecoin's own home page, if this is a true picture of profit, why would I rent my rig for less than this?
http://home.digitolle.net/miner/middlecoin.php(and if I am oversimplifying it, please let me know where my issue is and I'll attempt to correct.)
You assume that all Unexchanged and Immature is paid out at the end of every day and restarts the next day at zero. This is false and throwing your calculation off badly.
You are also dividing (BTC between 3AM and now) by (average Hash Rate) causing other errors. It causes it to drop to near 0 right after a payout and climb to steadily as the day goes on.
If you want to see it clearly, check your site at 2AM UTC right before the payout happens, it will show something like this:
(13 BTC Immature) + (127 BTC Unexchanged) + (400 BTC Balance) = 440 BTC / 21200 MH = 0.0225 btc/mh/day
Then an hour later after the payout has happened, it will show something like this:
(13 BTC Immature) + (127 BTC Unexchanged) + (10 BTC Balance) = 150 BTC / 21200 MH = 0.007 btc/mh/day
In reality, 390 BTC was paid out for 21200 MH, or a total of 0.0184 btc/mh for 1 day
Check it in a few hours and see for yourself.
If you want an accurate estimate for the current day, ignore Immature/Unexchanged as they stay somewhat constant. Then calculate:
Balance * (Hours since last payout)
----------------------------------
Hash Rate * 24
Right now, that works out to be:
330 BTC * 20 hours
------------------- = 0.01297 BTC / day
21200 * 24 hours
It is not exact as it assumes all BTC is paid out each day (in reality, only about 90-95% is, the rest is small amounts less than 0.01 btc per miner), and that Immature/Unexchanged is constant and it can vary quite a bit on some days, particularly if the exchanges are running slowly.