Why data transmission fails after pin hibernate while using XBEE-PRO-S2B

In my case, my end device is battery powered. So for the purpose of battery saving I am using XBEE-PRO-S2B module in pin hibernate mode. The end device wakes up after every 5 sec for transmission only and instantly goes to sleep. After wake up a loss of data packets in between after every 5-6 sent packets is observed.For it to get sufficient time to associate, I gave a delay of 1 sec in between wake up and transmission though I am not getting any positive results. Before S2B I was using XBEE-PRO-S2 module which was working perfectly fine where the delay given for association was only 3 msec. Kindly suggest me if there is any difference in the settings of PRO-S2 and PRO-S2B which i need to do and what is the exact time taken by S2B for association to work perfectly in pin hibernate mode.

Simply set the ST time on the parent node greater than your longest sleep time of your end device. That will keep the association and allow the data to flow quickly.

Thank You, it worked.