This is just an FYI...
Struggled with setting up IIC for a few days, robot calibration wasn't updating properly. It turns out that to use IIC each robot's software needs to be on the same exact version including minor revision. Minor revision is the number after the slash in the overall software, as in "11" in the case of V9.10P/11. This can be found in a teach pendant by Menu > Utilities > Hints.
In the case of a minor revision mismatch - To get two (or more) robots on the same minor revision the Autoupdate tool can be used, found under Software Downloads on Fanuc's CRC customer page. Another helpful hint: use a SanDisk flash drive, preferably a smallish one (I used 8GB), empty and formatted as FAT32, and put the Autoupdate files in the root directory. I was having issues when using an off-brand flash drive.
Update: had two robots on entirely different versions (8.30 and 8.40 or such) and had to buy an update from Fanuc. Probably should have fought them about it as we had already purchased IIC and this seems to be a pre-requisite of IIC working.