I do not believe it's going from 1000 polygon faces (PS2) to 1,500,000 polygon faces (PS3). I believe the source art for normal mapping is 1.5 million but the actual amount PS3 will display is probably more like 150,000 at the most, maybe only 15,000 (face alone) which makes more sense.
a 15x increase (1000 ====> 15,000) is very likely and very reasonable. a 150x increase is within the realm of possibility even though it's very unlikely.
but a 1500x increase? that is sheer nonsense and should not be believed.