I Think a lot of the delaying thing comes from individual JWS. We even went through a period of many commenting as such at the meetings. Thier reasoning was that Jehovah was delaying so as to alow more righteous people to come into the truth. Of course the bible says the end would delay not or something to that effect. The society even says it would not delay. As i told my wife , if Jehovah was delaying to alow more to come into the truth, then the end would never come, because you could keep bringing more in. It is typical of JWS reasoning , which of course isn't.
I think they may have got the idea from the "keep on the watch brochure" quote "Gods temporary permission of hardship has allowed time for others to embrace the truth" and "He will end wickedness at the time that is best for the settling of the issues forever...." The society being ambiguous as usual.