DIO transport delay

I am trying to get the best response time for a DIO signal between two xbee S1s (802.15.4). Using two microcontrollers and xbees, I send a DIO1 signal from one xbee, receive the DIO1 signal on the other xbee, and then retransmit on the DIO0 line back to the first xbee DIO0 line. The key transport delay will be in the xbee send/receive. For the first test, I used 9600 baud. I get 10.59ms for the one-way delay (two-way divided by 2). The 10.59ms was rock solid with no jitter.

I did a second test with 57600 baud. There I also get the exact same consistent 10.59ms delay. Does this make sense that the DIO transport delay is independent of the baud rate?

I was hoping for a shorter delay. Any way to speed up the DIO?

Yes that is correct. The use of the DIO line passing function is independent of the UART so the UART baud rate has no barring on it.