The Loop Back Test fails on Xbee Pro S2B why?

I have configured One S2B as Coordinator and Second one as Router. When I initiated Loopback test from Router by making cluster ID=12, it is perfectly fine, but when I did it from coordinator I found sever timeouts and the connectivity is not reliable. Communication is very poor. For your information both the modules are kept side-by-side and connected to the same laptop with two different com ports. Please explain why?

Simply, the coordinator is in broadcast mode and requires about 2 to 3 seconds of delay between each packet in this mode. Try switching to unicast mode instead.

No ! I won’t be able to switch to unicast (one to One) network because I am setting up multicast with One coordinator with 15 routers. If this is the kind of delay and reliability then the very idea of Point to multipoint is defeated. If response from our Micro controllers are delayed, the purpose of such network becomes questionable.