Clean install High Sierra - APFS encrypted boot password keyboard problem

Wanted to share this experience for information as much as anything, although I welcome any comments.

I installed High Sierra over Sierra using the standard App Store procedure. I then thought to do a clean installation to clear up a couple of minor but irksome (Keychain) issues and at the same time clean out the drive. So I hit Command-R during a reboot and went to erase the disk.

Anomaly 1 - first reformat seems not encrypted despite Disk Utility prompt 'APFS (Encrypted)'

The default format prompt in Disk Utility was 'APFS (Encrypted)'. I took this option but after completion the file system was listed as 'APFS' (without encryption). Reformatted a second time and Disk Utility prompted me for a password. Tried this back and forth several times to make sure I was not seeing things (SSD still intact despite scrubbing the boot blocks a few times) and Disk Utility seemed to work, prompting / not prompting for a password as expected, and then showing the expected encrypted / not encrypted result. If I remember (sorry, it was late), exiting Disk Utility and going back in may have caused a recurrence of the anomaly.

Anomaly 2 - keyboard failure when entering boot password during High Sierra installation

This was more irritating. Having confirmed that I was not going insane / blind and that (above) this was Disk Utility doing odd things, I proceeded to install High Sierra after formatting as APFS (Encrypted) and setting a password. After around 15 minutes of installation I saw a black screen and a prompt for 'Boot Password'. Tried to type in my password but the 'm' key would not work. All other keys on my (integrated) keyboard operated fine, but not the 'm'. Naturally, the password had an 'm' in it, didn't it?

Had to switch off the machine and reboot. At this point the machine had no active O/S and I'd not hit Command-R (by this time it was very late) so the wretched thing proceeded to download (the old) Sierra. Rebooted and used Option-Command-R and finally got High Sierra back into the restore partition.

After this I went back to reformat and do the installation. Managed to re-create the same anomaly (1) with the AFPS format and Disk Utility not setting the correct encrypted status. This time I proceeded without encryption to avoid the keyboard problem, then when doing the final steps of the installation selected to use FileVault, which I assume results in the same format and security outcomes as setting encryption at the time of reformatting. (The 'm' key had worked fine when I typed in the password and has been all right ever since.)

In sum and to save others from wasting time (so many recent posts in the tech media on 'clean install High Sierra' but none covering anything but the obvious), my solution to this clean installation problem was to format to 'APFS' (unencrypted) and then encrypt by selecting FileVault when the O/S came to life for the first time.

Finally, if you can be bothered and have better tech knowledge than I, do let me know if setting encryption with FileVault is in any way different from / less secure than setting it at reformat time. I rather hope not. I should be interested if you have experienced a similar keyboard problem with a boot password - my MacBook Pro 15' is only 6 weeks old and I believe the keyboard (physically) is fine. Likewise, did not see any posts on this during the Beta phase.