Regardless of what Tier a powerful engram is allocated, at no point should any one item your receive be lower than any you currently have regardless of Total light level.
How is it that the PRISMATIC FACET is able to detect a knockout list of items.
But Powerful engrams cannot detect a piece you have higher than your current overall light so it will drop you a piece lower than that said item?
For instance
OVERALL LL = 562
CHEST PIECE = 566
POWER ENGRAM CHEST PIECE DROP = 563. (SHOULD DROP AT 567)
POWERFUL engrams are supposed to implement PROGRESSION but in most cases do not live up to their name.
Exectations for INCREASING POWER is why most players engage THEIR TIME in those activities and it is extremely demoralizing to receive something lower rather than higher than any gear.