Three into two
Students in schools or colleges studying five subjects in their first year will have to take 15 units. This will presumably equate to 30 or 45 periods per week - a tall order for any student let alone the school which may have fewer than 45 periods on the timetable.
A two-unit AS block would be much simpler (Edexcel mathematics is a popular example in current use) and might just save the idea from being strangled before birth.
G B Attwood The Cross Repton Derbyshire