It's clear to me that the WT quite simply makes things up as they go along. When they're exposed on any doctrine, belief or practice, they use the "imperfect men" card and call it a mistake. I call it intentional deceit.
The only mistake the WT continuously makes is forgetting to ensure that any of their "New Light" is not actually a flip-flop from a previously made up interpretation of scripture (like the Toes on the statue).