In VBA not an expert, but had to face. You do not understand. Normal array plPath.Coordinates, but can't get it the first element.
MsgBox TypeName(plPath.Coordinates) ' Double
MsgBox UBound(plPath.Coordinates) ' 7
MsgBox IsArray(plPath.Coordinates) To ' True
MsgBox plPath.Coordinates(0) ' Error 451: Property let procedure ...