When performing an upgrade installation (remove old version and install new version using automated method in the installer), the settings for default page size are lost. Settings should not be removed when uninstalling for an upgrade. This should probably be a prompt as part of the uninstall process.
Edit: This applies to the current version. I upgraded from 1.2.0 to 1.2.1.
Bonus: If there were some locale settings for default page size, this should be used instead.