They allows trains to reach before time. Most BBS bound trains arrives early at VSKP. Also leaving PF1 will not block all the lines all cases.
If a train leaves from PF1 goes towards HWH, then admitting train from bza side to VSKP is very much possible.
Its a clear mismanagement at ECoR for many years. Yesterday Kirandul passenger detained at SCMN for 1 hr even though PFs are free at VSKP.
VSKP...
more... to GPT 3rd line needs and also trains should start parallel like BZA to EE side. They too much load can be reduced as SCM to VZM it has 3 lines.