I believe the reason for the Oracle change is because to keep it's original formatting it'd be this:

Infernal Contract
BBB
Sorcery
Rare
As an additional cost to cast Infernal Contract, lose half your life rounded up.

Draw four cards.


The problem with this version is that if I play it at say 15 life, I'll lose 8 life...even if you counter it because I've had to lose the life as a cost of playing the spell. Now you only lose the life upon resolution.