Don't worry, you'll understand once you encounter someone who tries to specifically lie about the content of your posts by making the said content up.
Actual title: the holder is considered a champion and is obligated to unify his title with the interim champion the moment the said holder is capable of fighting.
Interim title: the holder is considered a champion and is obligated to unify his title with the actual champion the moment the said champion is capable of fighting.
Actual title: if the holder is incapable of defending the title once the unification date is set, he is stripped and the interim champion becomes undisputed.
Interim title: if the holder is incapable of defending the title once the unification date is set, he is stripped and the actual champion becomes undisputed.
Seems equivalent to me. The only difference lies in the fact that the unification date depends on the date the actual champion is capable of returning and is not set by the interim title holder, but this difference stems from the fact the inactivity of the actual champion is a condition for the interim belt to me made in the first place. In this context, the actual champion has a certain privilege, but the titles are quivalent.