Acording to this reference:
It is not a very well known fact, but all hard disks have a very
strong hardware password capability build in. This password is usually
stored both in a chip on the HD controller (the printed circuit board
on the hard disk) and on the hard disk itself in a special hidden
Setting this password will make the hard disk completely unusable to
anyone that doesn’t know it. And not only on your computer, but on any
A lot of newer laptops will set the HD password together with the BIOS
password, completely locking all the hardware.
The hard disk manufacturers are unable to unlock a password protected hard disk, as there aren’t any “secret” master passwords
build into the firmware. Even swapping the controller of the
password-protected hard disk with exactly the same controller from an
unprotected HD will not remove the protection on most disks, as the
password (together with most of the firmware) is also stored on the
hard disk itself.
The only way of retrieving any files from a password protected hard
disk without knowing the password is to send it to a data recovery
company for unlocking, but not all data recovery companies could or
would unlock a password protected HD.
In this time of rising identity theft, protecting your personal data
by locking your hard disk with a password is indeed a good idea. The
downside is that when the HD eventually malfunctions it will be harder
or even impossible to retrieve any files from it. So, the first rule
of using a computer applies here in full strength – “Your data is only
as good as your latest backup”!
This means that BIOS HDD password is not a encryption of your HDD(SSD on your case), but only a "lock". All your data inside your SSD will be protected due to the fact that the SSD reading is locked by the BIOS password, but the data by itself is not exactly encrypted. Assuming this, I can see no difference from inserting a BIOS password before or after Windows installation, both cases will work and both will lock SSD reading, but to make things easier I would set this BIOS password lock only after Windows installation. I mean, Windows installation will restart the machine some times to complete installation and everytime you must insert the BIOS password, this is the only reason to set it after.
There is also another reference here on SU about HDD BIOS password.