Just to let you know I received a response to my Query when asked through the Facebook page, please see below;
“Thank you for reaching out to us. Tiered tariffs are currently not a selection/feature that can be set in the app. We have sent that type of request to our development team to see if they can add that as a feature, but as of right now we don’t have an ETA on if and when that may be a possible feature in the app. Please let us know if you have any other questions.”