If you creating a new vDisk Version, parent Disk – ahvd(x) and booting up your Base Image with that Version (PVS: boot from vDisk), it’s also possible to run BIS-F after your changes. BIS-F detect the BootMode and do not run P2PVS / ImagingWizard to convert the Disk (not necessary in this stage).
BIS-F run’s all the other needed preparation steps
For avhd(x) also a defrag will not performed, if you have it enabled in the ADMX. Further information’s about defrag can be getting here