Whenever my Xert code changes I have to manually enter it into every Xert IQ App I downloaded. Is this normal? If so, is the automatic sync foreseen?
Garmin’s CIQ datafields do not support automatically obtaining configuration settings at this time. This is a feature that is being planned by Garmin in 2017.
https://developer.garmin.com/connect-iq/programmers-guide/communication/
“Widgets and apps can communicate with a mobile phone via Bluetooth Low Energy (BLE)…”
But not ConnectIQ datafields. 
Datafields are preferred as they can be displayed together with your other workout datafields - cadence, distance, etc. - during an activity recording. Widgets and apps have to run the entire Garmin interface and can’t be integrated into your activity profile.