XBee Pro latency

I’ve set up a channel between two XBee Pro modules. RR=0, the DH/DL addresses point to the other’s SH/SL numbers, both units are running firmware ver. 10A5, PAN ID=FFFF for both. MY=FFFF for both.

The problem I’m having is that I am not able to send packets from one unit to the other without incurring a delay ranging from 1-20ms. It’d be OK if it was a constant delay, but it varies by the above amount.

Does anyone have any suggestions as to how to use these modules for unidirectional, unreliable transport of small packets while keeping the latency jitter to a minimum?

Thanks in advance!