These are 4 MPUs. "Travelling" from one to the other is a vertical leap in this diagram. This would not benefit the traveller with any foreknowledge. In fact, the traveller would be confused as to why things are different from the way they remember them.
In order to see future trouble or change the past, the traveller would have to move horizontally on the diagram.
There is an inherent error in this logic though. If Desmond were in fact 'time traveling' to a time
when he was alive he would see himself, as did Bruce Willis in "12 Monkeys". Bruce Willis traveled to a time when he was a child at a location where he as a child was, and in fact, 'saw himself'. Desmond has traveled to a time in the past where he was (confirmed today by DL and CC that Des did in fact, "time travel")- but he did not see a carbon copy of himself. He in fact, was "himself". He embodied himself physcally but carried with him the foreknowledge of events past and future. That's why I was alluding to the fact that he only 'mind traveled', not true time travel as in the physical human body goes from one location to the other, but his mind, fully armed with facts and knowledge from 'his future', went back in time.
I don't agree with the assumption that travelers in MPU's are locked 'parallel in time', that is, you can't jump up or down, future or past on the time/space continuum,- meaning you can only stay in the same 'time frame' of each MPU as the one in which you just left previously. I[m not sure that the MPU's even have to be all in 'lock step' time wise, that they are all on the same parallel path. But if time is 'non-linear', as we have seen with almost all instances of time travel or MPU's in movies and TV, then the traveler does not have to respect the linear aspect of time as we here on Earth know it, and as someone else mentioned in a previous post, time is 'morphing' all around us all of the time, and we just move from one time slot to another. We just percieve it as linear, because that's the only thing our terrestrial brains can comprehend.