Decrement timestep where necessary to avoid well post-configuration.
Consider the following:
.
.
.
WELLSPECS
'W1' 'G1' ... /
TSTEP
2*1 /
WELLSPECS
'W1' 'G2' .../
TSTEP
2*1 /
In that case the parent group of W1 is changed after two timesteps. At timestep
two the Group parent will indicate G2, while the GOPT:G2 at timestep two should
be reported for what has progressed up until timestep two.