Polled Method & low power usage (Battery powered)

with Xbee S2C, how to conjugate the low power usage (battery powered for endpoint, router) and polled method between endpoint and coordinator (in order to disable collision) ?
Since in this case, all endpoints waiting when it must sent data (ie so don’t sleep, ie no Cyclic Sleep SM=5 or 4)?
Best regards.

If the coordinator solicits endpoint in a pre-established order, and that hourly. A scenarion could be that the package coordinator, sent to an endpoint to request it to send the data, the timestamp might contain coordinator (their local time). Suddenly, the endpoint 1) know that it should send these data, 2) realigned its clock, 3) goes back to sleep for 55 minutes? I’m wrong ? or better way ?
Best regards.