I suppose it depends entirely on the airline and the views of the training department as to what is necessary. I got 60 sectors as a baby 200hr F/O and I understand my airline has now reduced this to 50, with the stipulation that once you are up to line standard you can be line checked prior to actually reaching the 50 sector mark. I can only go off my individual experience but 100 sectors in a short haul environment seems like a lot to me, particularly when you consider how much of a strain that must put on the training department. You would need a lot of training captains with flight duty hours to burn to give every low hour guy 100 sectors to reach line standard!
Maybe they are suggesting you can have as many sectors as is necessary up to a reasonable amount, ie, 100?