My thoughts exactly, "si vivis...". What harm does it do?
Even conditional administration of the Sacraments is considered wrong if there's no reasonable chance it could be valid. It would still be an offense to the Sacrament if you tried to administer it to someone who's been dead 3 days even if you were to throw in a "si vivis". Thus the rule of thumb about generally how long afterwards you can administer the Sacrament.
I don't quite understand why it's 2-4 hours if someone dies suddenly vs. 30 minutes if someone passes away from a drawn-out illness.