It seems that they often lay the groundwork for a planned change years in advance so that when they make a change, all the JWs think "It's about time they did that!" and their faith isn't rattled. They think they thought of it first and that this is a sign that they are connected with god because they anticipated a change that his organization eventually made. If someone were to get wind of an organizational change that they don't expect, they want to understand why - they look for a reason for the change. If they have a reason for a change ahead of hearing of the change, they're more likely to accept that the reason they already have is the true reason for the change.
In this case, they print an article or two that elicits answers talking about how the stats are wrong, then they stop printing the numbers and everyone says "that makes sense" and not "they're trying to hide something." Instead of people looking for the reason they stopped printing the numbers (which might entail looking at the past numbers and causing them to question things) they'll just accept the reason given.