For many months, changing the number of "lane change" turn signal flashes from 3 to 5 via coding hasn't worked for most i3 drivers. A Facebook i3 group member discovered that resetting the driver profiles after changing the coding will change the number of "lane change" turn signal flashes from 3 to 5. I have verified this on our 2014 U.S. i3 with system software version I001-18-11-520 (i.e., the November, 2018, version). However, restoring the driver profiles from a backup will revert the number of "lane change" turn signal flashes back to 3.
The bottom line at this time seems to be that to have 5 "lane change" turn signal flashes, profile restorations cannot be made which eliminates the value of backing up profiles so that they can be restored, if necessary, an unfortunate requirement. So if you want 5 "lane change" turn signal flashes, after resetting your driver profiles, you'd need to laboriously reset the side mirror positions, the pre-sets, Eco Pro settings, and a number of iDrive settings that aren't completely obvious until one notices that something has changed.
One possibility that I didn't check is to uncheck the iDrive setting that enables 3 "lane change" turn signal flashes prior to backing up a driver profile, resetting the profile, restoring it, and then manually checking the iDrive setting that enables 3 "lane change" turn signal flashes. I would check this possibility if it weren't likely that I would have to once again manually set all of my settings that are stored in my driver profile. If you try this, please post your findings.
2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE