The lines are, like in problem 3, due
to a large post-thrust integration time-slice.
However, there is no real maximum in this pictureand
the slope of the ramps in part A is
opposite to that in part B. The
reason for the inversion of orientation of the ramps
is probably due to the fact that the maximum is above
and to the right of the letter A on
the diagram and at the lint drawn across the middle
of the plot, the lines run towards the maximum.
The reason for the not being a real
maximum is because the time limit on the model is set
to a time that is significantly shorter than the time
of the flight. Short time limits are useful for
examining the early stages of flight but they can
cause some curious results in inappropriate output
variables such as this one.