I don't see the parallel between Noah's preaching and the events from 1914. I guess the WTS has to keep adding periods on to old dates that give an end date somewhat in the distance (so it won't be reached soon) but not too far that many give-up now. To say absolutely that the end is 2034 would mean for many that it's not within their lifetime...I will be 74 in that year.
To say that God fixed a 120 year period from 1914 implies that the warning work that parallels Noah's commission to build an ark began in that year. What then of the 35 years prior to 1914 when C.T. Russell was warning that the end was coming 40 years after 1874 (Christ's first invisible presence)? Was that a false start? Was Russell only given enough insight to predict the start of 120 year final period? What about Russell's 1799 date for the start of the "time of the end?" 120 years added to that date would be 1919.
If Jesus didn't approve the board of directors of the Watchtower, Bible & Tract Society as his true representatives on Earth until 1918/19 (which is actually 1260 days after the start of something else never clearly defined) who was doing the warning work between the fall of 1914 and then? If it was Russell why discount his earlier work? Anyway, the "last days" project kick-off didn't happen until 1919 in Cedar Point, Ohio so why not add 120 years to that date? (Maybe this is future new light to be announced around 2033.)
The whole idea of 120 years from 1914 is a bad fit with current Watchtower doctrine on dates. It is pure clutching at straws to make a date act as a "carrot" for the members and reduce the declining membership.
3rd