Why does the --percent option in kickstart not properly utilize the available free space in Red Hat Enterprise Linux 6.7?

Issue

• Why does the --percent option in kickstart not properly utilize the available free space in Red Hat Enterprise Linux 6.7?
• Kickstart partitioning is as follows.

part /boot --asprimary --fstype ext4 --label boot --size=500
part pv.01 --size 32768 
volgroup vg_sys --pesize=32768 pv.01
logvol /              --fstype ext4 --name rootfs  --vgname=vg_sys --size 250 --grow --percent=20
logvol /home          --fstype ext4 --name home    --vgname=vg_sys --size 100 --grow --percent=10
logvol /opt           --fstype ext4 --name opt     --vgname=vg_sys --size 1   --grow --percent=10
logvol /tmp           --fstype ext4 --name tmp     --vgname=vg_sys --size 1   --grow --percent=10
logvol /var           --fstype ext4 --name var     --vgname=vg_sys --size 384 --grow --percent=30
logvol /var/log       --fstype ext4 --name log     --vgname=vg_sys --size 1   --grow --percent=10
logvol /var/log/audit --fstype ext4 --name audit   --vgname=vg_sys --size 1   --grow --percent=10
logvol swap           --fstype swap --name swap    --vgname=vg_sys --size 4096

• With Red Hat Enterprise Linux 6.6 final partitioning after installation is:

[root@]# vgs
  VG     #PV #LV #SN Attr   VSize  VFree  
vg_sys   1   8   0 wz--n- 31.97g 320.00m
[root@]# lvs
  LV     VG     Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  audit  vg_sys -wi-ao----  2.69g                                                    
  home   vg_sys -wi-ao----  2.78g                                                    
  log    vg_sys -wi-ao----  2.69g                                                    
  opt    vg_sys -wi-ao----  2.69g                                                    
  rootfs vg_sys -wi-ao----  5.62g                                                    
  swap   vg_sys -wi-ao----  4.00g                                                    
  tmp    vg_sys -wi-ao----  2.69g                                                    
  var    vg_sys -wi-ao----  8.50g

• Starting form Red Hat Enterprise Linux 6.7 (6.8) with the same snippet one gets completely different partitioning schema:

[root@]# vgs
  VG     #PV #LV #SN Attr   VSize  VFree
  vg_sys   1   8   0 wz--n- 31.97g 9.25g

[root@]# lvs
  LV     VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  audit  vg_sys -wi-ao---- 992.00m                                                    
  home   vg_sys -wi-ao----   1.59g                                                    
  log    vg_sys -wi-ao----   1.09g                                                    
  opt    vg_sys -wi-ao----   1.34g                                                    
  rootfs vg_sys -wi-ao----   4.00g                                                    
  swap   vg_sys -wi-ao----   4.00g                                                    
  tmp    vg_sys -wi-ao----   1.22g                                                    
  var    vg_sys -wi-ao----   8.50g

• Why is this changed?