But in practice, when the lead follicle goes over 16, all the extra dose will be absorbed by the leading one(s) - it is the nature's winner takes all. So I am actually against kicking in extra dose, which is only helpful before the lead follicles are very established. The extra dose that goes into the lead follicles may cause them to be over mature and therefore hurt the quality.
Adding extra dose will help before the lead follicles get over the 14 mark. Once they are over 14, they grow at 3mm per day, and there is no holding back despite ganirelix.