if you must type your password several times,
that's because you set it up that way.
The default LVM setup with encryption, only encrypts the Physical Volume (LVM)
Within the Physical Volume you add Volume Groups, and finally create mount points.
Now, for each created mount point, you have the availability to encrypt it.
This way, (especially for paranoid users
) encrypted systems can have several passwords.
at boottime, you will be asked for those passwords, otherwise the system won't boot.
And i believe that this is what happened in your case., i think that you encrypted your mount points.
you can see it in the picture below: only the Physical volume has a Lock-icon,
the mount points stays un-encrypted, because they already excist in a encrypted Volume.