As a good approach to decrease the data traffic and energy consumption in wireless sensor networks, innetwork data aggregation has been concerned widely in recent years. Monhamed [2] presented the TiNA scheme, namely Temporal coherency in-Network Aggregation, which utilizes the end-user tolerance to temporal coherency to minimize energy consumption of wireless sensor networks and provide high quality of data at the same time. In this paper, we modify the original TiNA algorithm by adding an external data item used to keep the last sampled data reading. It is shown that by recording the enough intermediate reading information, the proposed E-TiNA algorithm can provide better quality of data at all kinds of cases.