It appears the read only command (%V) for supply voltage, is different in the XB24C SMT device, from the XB24-ZB Through Hole XBee.
The XB24-ZB requires some math. (%V * 1200/1024) to derive the battery voltage or VCC.
The XB24C %V returns the battery/VCC in mV if I understand the manuals correctly. Measurements support this.
For me, this creates a complication when migrating to SMT devices in an existing Through Hole network where battery voltage is monitored, and decisions are made based upon battery condition.
Not only will battery level have to be monitored; Xbee type will have to be read to determine the math to use on the %V reading.
Perhaps there needs to be a setting to determine how %V will be available to read.