Hey I am a bit busy right now with real life but I'll be back soon 
Feel free to change the arduino code in the way you think it will work best and if so well add your changes to the xoscillo codebase.
Sending data only when it changes is a good idea, the problem is that data is changing all the time, the interrupt would be triggered continuously and this would be a big slowdown... what you mention would be good if the signal was to change slowly or remain constant for long periods of time, which is not the typical case.