This is a weekly activity. You can repeat the weekly activities in a certain day of the week (e.g. every Monday). Remember that A17 to A21 should be run in sequence.
The purpose of measuring progress is to find deviations and fix them.
The forecasts for time and cost are compared to the targets in the Progress Register. If there are deviations, you should compare them with Plan Limits. If both time and cost forecasts are below their Plan Limits, then the Project Manager decides on how to fix them. Otherwise, it means that you cannot meet the targets, and you should find a serious way for fixing the problems. The issue should be escalated to the Sponsor, and everyone checks the possible solutions. When the Sponsor selects a solution, it will be reflected to the plans using the Cycle Planning activities (A12 to A16).