SO spotted this post about leveling using the companion app > eusgamer.blogspot.com/2017/06/leveling-from-100-to-110-is-now-lot.html. Just want to ask if this can make my 101 rogue to 110 in a week.
I've just copied the process below for those who are also wondering on how to level up using the companion app.
1.) Get your alt to level 100 and proceed through the order hall campaign long enough to unlock two followers.
2.) Farm Blood of Sargeras on your main character by questing, completing order hall missions, or dungeon-ing.
3.) Visit the Blood of Sargeras vendor and start trading Blood for Order Resource Cache. The exchange rate is 1 Blood for 200 Order Resources.
4.) Send all of the Order Resource Cache items to the alt you plan to level via the app. Some reports say the full leveling will take about 10k Order Resources.
5.) Log on to your alt and claim the Order Resources from your mail.
6.) Log in to the app and start completing missions. It is very important to complete all of the available missions, even the ones that don’t reward bonus player experience. Completing the non XP missions will make them disappear and increase the chance that they are replaced with XP missions.