The model used for Flow is "branch on disagree" or "branch on digress". That model is not obvious if you want to mark a comment where you disagree on last reply. Then you must wait for someone to agree on last, before you can disagree on last. Otherwise you must accept a model where posts always are a "disagree on last", but that is neither correct.

Either the intent of the post must be added, or an other reply model must be devised.

The full list of feedbacks can be found on w:no:Wikipedia:Torget#Flow (permalink)