Even if we take the high end of PC estimates it's obvious that EA's decision to port to consoles has paid in spades. The original could sell 2.5 on PS360 or almost 3 times the PC version LT. If DLC like awakenings sells another 1.5m at $40 the IP went from recovering 5 yrs. dev. costs to some real profit.
IMO the PC sales will tail off more quickly because of piracy and dlc sales must compete with a strong mod community. Smart move for a small sacrifice in Bioware's reputation for quality.