This organization has a history of making thing up, claiming the bible says things it doesn't and making date predictions based on pure speculation. When these predictions fail, instead of learning from their mistakes they just make up new things that will also inevitability fail. It's a consistent pattern designed to keep people feeling the urgency of impending destruction. You can't have a doomsday cult without a doomsday looming.
1914 is a perfect example. Prior to 1914 they believed they were already in the last days and Armageddon was going to be in 1914. When that didn't happen they invented the "invisible presence of Jesus" and still said Armageddon was imminent. For years they taught that the end would come before the generation of 1914 passed away. When that became impossible to keep up anymore they made up the ridiculous "overlapping generation" doctrine. Who know how many overlaps they will get out of that before they have to come up with something new?
They are not just making innocent mistakes, and then correcting them, it's a pattern. They claim to be directed by God, people believe them and make life decisions on their made up doctrines. They never admit their past mistakes, hide their history and go on deceiving people.