Continuing with Vatican II on anointing of the sick:
The number of the anointings is to be adapted to the occasion, and the prayers which belong to the rite of anointing are to be revised so as to correspond with the varying conditions of the sick who receive the sacrament.
The number refers to the practice of anointing head and hands, I suppose. The current rite for Pastoral Care of the Sick has a wealth of prayers, much of which were new compositions coming from the post-conciliar period. Nobody seems to complain about it.
Catholic Sensibility 
I think the “number of anointings” refers to more anointings that were part of the prior rite, but no longer.
I don’t know what all those anointings were, but as it is, the priest has the option of additional anointings now: the idea is to anoint that part of the body that is hurting. I make the offer when it seems convenient, and some take me up on it.