For those interested.
Well, after a couple of testing I can confirm the calculations changed somehow without notice, right during/after the payout issue of two days ago.
I started mining here around August 2, invited two more friends and a neighbour who contributed both small rigs and rentals, we shared computers, internet connection and also placed bets, jokingly, to see who among us would be the first to get an S3.
For an estimate of payouts we were using a modification of the formula suggested by ckolivas in bitcointalk.org/index.php?topic=104251.0,
to great success all the time up until two days ago. Quoting him:
The equation is that approximately every 4.2 GH you will find a (difficulty 1) share on average. So 1GH/s will find a share every 4.2 seconds. With 86400 seconds in a day, this equates to 86400/42 ~ 20,570 shares per day per GH/s.
The aforementioned formula plus other stats-math worked amazingly great –we were predicting our payouts per desired time lapse with very good accuracy. We felt confident and started renting to add up, and it was amazing. Together we ended up contributing ~100 Th/s to the pool.
Long story short, if you go to bitcoinwisdom/bitcoin/difficulty and put 1000Gh/s you get 0.02109 as per current diff daily payout.
Theoretically, if you rent for the same price per Th/s and have 100% efficiency, you get around 12,5% because of the bonus, plus a slight difference in the PPS value BAN uses (higher), minus fees (network tx + 2~3%rental). As everybody knows this is not written on stone, but it worked great for us as an estimate with the addition of some stat calcs.
Even s0br suggested having a look at that site.
Renting at less of that price implied better, calculated profit. Even renting at 0.0233 (@ current diff) proved to be slightly profitable.
As we felt comfortable, we left the system working without checking/tweaking all the time and that's when the loss happened.
The aforementioned method does not apply anymore. Even renting at the theoretical price now implies a loss, and that happened out of the blue as we were investing the money to rent around ~100Th/s together.
One of the testings mentioned was a simple one. Use an empty wallet address, transfer some btc to the rental site, rent a rig at a specific price, do the math, wait the final payout @BAN, do the math.
We tried different amounts. For instance in one test we tried 0.152 btc, we expected by our working calcs 0.179 btc at a specific price, the worker was 99.98% efficiency on ireland server (great one), however we've got 0.132 btc final. Lost ~0.02 btc. That's a 13%!
No problem, it was a test. Imagine the loss with bigger amounts.
I would like to stress that the problem is not the profitabilty but the
lack of communication or warning that the calcs are about to get tweaked or changed. That's in my opinion an important point to build up confidence. I'd like to mine without being worried the pool changing the "math/payout rules" all the time without notice.
We are so grateful with both the original proposal and ways of the pool's admins. I understand there are risks involved, me and teammates accepted that. We are all "beta testers" here and it sounded great to me, but we cannot afford another big loss as the last one was.
So I have to say "hasta luego!", from the unusually warm winter of Southern Hemisphere.
Have fun and good luck with your upcoming projects everyone.