That's one of the reasons why it is so hard to predict/estimate the amount of btc/mh/day for most pools like ours.

The most accurate way we have found, is to use several mining machines with ~1mh/sec hashing power (as reported by cgminer) and average their payout as our benchmark. Which is what we have been doing for the past couple of days.

Our difficulty is compounded by the fact that our pool of miners are constantly mining different coins, and there are too many variables to take into consideration, e.g. will the exchange rate differ significantly from the block's maturity until it is sent and traded on the exchanged, orphaned blocks etc.

For a safer alternative, I'd recommend you allocate a portion of your hashpower with us, for a day or two, to see our payouts before committing your entire hash power. I apologise that we are unable to provide you with more accurate estimates at this point!