My daughter has taken AS exams in Biology, Chemistry, Physics, maths and Further Maths this summer.
DS has just done the same; in my opinion the workload for Maths and Further Maths has been at least as much and probably more than for the three sciences combined during Y12. DS isn't showing much enthusiasm for dropping any of his subjects and my concern is that the volume of Maths work at A2 will dilute the grades that he might otherwise have achieved in the science subjects.
Having said that, his OCR exam timetable was quite kind and spread evenly over five weeks so it would certainly help if the same happened at A2. But getting some of the modules out of the way in January 2014 would have been even better!