In the August broadcast Bro Splane explains this point deeper.
When the brothers are sitting together and joyfully speaking about clarification of JW belief, they often encounter and deal with that "Domino-Effect" when one scripture has effects on others. So all Changes are carefully considered before they come into print, one after the other but late.
Lately he mentions the "Godfathers" brother Jaracz , Barr as good examples of reading the bible progressivly, they were very progressive at there time. What ever this could mean he did not explain it?
However certainly already back then they got into contact with that dangerous Domino Effect if they touched one scripture and wanted to clarify it carefully and probably they tried but could not cope with the effects and changed nothing important for the benefit of us.
And what are these guys thinking about to change at this moment, when their bibles come on the table?
BTW: If the Domino effect is to be blamed for that, how LARGE has been the HERESY up to now, it must have been immense? How many false prophesies must have JW made that a clarification is pratically unimpossible due to those random-effects on other prophecies. Think of that.
Listen the Youtube video from minute 25:10