Having watched over 115,000 coins worth of ads, our observation is that there is a limited amount of ads available on the app that are delivered as "first come, first served". Ads roll over at 9 PM Tapastic Standard Time (midnight Eastern, New York City). We used to be able to watch about 1,500 in ads per night but now since everyone is watching ads, they are being depleted very quickly and if we get about 300 coins then we're lucky, as nothing is available again until the next cycle.
Due to the high demand for coin earning opportunities, Tapastic staff should look into adding more video inventory and also stretch out into other opportunities such as Peanut Lab Surveys as soon as reasonably possible.