1) talking of boundary markers: Jesus speaking to future members of the first non-wt Governing Body, Acts 1:7: " It is not given to you to understand times and seasons, which the father has put in his own jurisdiction" or (out of bounds). Perhaps Splane thinks it does not apply to him because Peter John and Matthew were not part of the Faithful Slave, but he is?
2) The other time boundary that jesus set, was with the generation. he said: it " --will not pass away until all these things " predicted, (including the end, after Armageddon), would occur; but with the anointed generation, wt has moved the time marker forward, with the anointed generation ending before Armageddon, when they are raptured off the earth.