Time to switch Xbee from RX mode to TX Mode

Hi,
I work with XBee PRO S2 with 2xA0 firmware and U/FL connector for antenn.

I send 25 Frames of 100 data bytes and the time for complete this action is 3s!

I search and I find the times for receive ACK is 120ms.
(The time for make Frame is 10ms ! )

I would like to know the time the xbee module is to switch from RX to TX mode.

Can you help me?

Thanks,
Stephane

I work in API mode