No you are right but neither recommend using Basmati which as a rice stands alone whereas Pilaf and Pilau rely on adding flavour by pre-frying in spices etc. Ordinary Long Grain Rice does for them.
Mind you I suspect that Pastis is right ~ he needs to play with the recipe a bit. Simply halving or doubling quantities never works.
It's fine to say two fish will serve two people so for one person you only need one fish but the rest is a blending of flavours and that depends more on taste than simply halving quantities ~ or at least that has been my experience