The extent to which that principle can be married to the traditional end-of-course Higher exam is limited, but candidates are offered at least one reassessment. Depending on how early the first test is administered, that may prove essential. Keeping candidates up tothe mark, which used to await upon the fraught results of prelims, is another argument for internal assessment during the session.
The irony is that the weaker the candidate the more attention has to be paid to providing for assessment and the less time there is for teaching and learning. Weaker peers are at more and more of a disadvantage as the months pass.
Providing for first assessment of work is not over-burdensome. It is a different matter to keep up with the progress and needs of individual candidates as the session advances and benchmarks remain to be achieved. The teacher becomes a harassed timetabler and marker.