Why there is a price difference for 9 cell battery for Dell Studio, and Dell Inspiron 15 New?

9 cell bettery for Dell Studio is Rs 1158.15,

and the same 9cell 80WHr batter for Dell Inspiron 15 New is of Rs 1580.60

Where there is such price difference. Can someone explain to me? .. is any one of them technologically superior?Why there is a price difference for 9 cell battery for Dell Studio, and Dell Inspiron 15 New?don't know the exact reason but may be due to difference in design and complexity of the battery, also the two batteries might have different size, a more compact battery may be a bit costlier.

also my inspiron battery has a meter, when a push a button on it, led lights glow indicating the charge level, this thing would definitely add up to the cost.