Order of Operations

2(−4)^{2}+ (6)(−4) − (−8) = 16

Why does this expression not equal -48? Should not it simplify to:

= -16 * 2 + (-24) + 8

= -32 -16

= -48

To my understanding, I am following the PEMDAS process to achieve -48; alas, my calculator disagrees. It would seem that perhaps either the 32 or 16 should not be negative? Any insight as to what operations I am performing incorrectly would be greatly appreciated.