The remainder of previous months is the money that arrived too late and never got a chance to be included into the finalized income of a given month. This money will be paid out in the near future.
Ad networks provide the corrected — but not finalized — income. For instance, as of February 28th an ad network income accounts for $100. Just the next day, on March 1st, this sum can change by a few dollars as an ad network makes adjustments. Moreover, some ad networks can be 1-2 days late with supplying information about payments.
When we are planning regular payouts for the beginning of every month, we are operating on the information we have at that particular moment. But this information is not final. It’s very likely that the networks need a little bit more time to finish processing the income. The loading of a full, detailed report can take up to five days (and even more in very rare cases). We do not provide estimated dates because different ad networks supply us with the final reports at different times. To calculate the most correct version of monthly revenue — so it’s stable and we won’t need to change it throughout the month — we use the actual information we have at the end of the month.
After the full revenue report comes in, we calculate the remainder of the previous months (the difference between the money you were paid and the finalized sum). This remainder can be positive (if the income is more than what we paid you) and negative (if the final revenue is actually less). The planned regular payout, though, will be made at the end of the month.