Sacrifice question.

[jwallstone]

This is a general game mechanic with spell durations. It's not just hypnosis, it applies to every spell. Spell durations are counted in terms of the unit's turns, not battle turns. For example, if a unit performs an action ending its turn, such as attacks, uses an ability, or defends, then the duration of every status effect (buffs/debuffs such as hypnosis) is decremented IMMEDIATELY.

It can be most noticeable with a spell like phantom. On the third turn, if you right click a phantom unit, it will have a status effect indicating that its a phantom, with a duration of 1 left. Now, if you perform any turn-ending action with it, it will disappear immediately. But if you Wait with it, it'll stick around until it's second action, distracting and/or blocking enemies for the turn. It's important to understand this mechanic to make the best use of your spells, as in this example with phantom.

Another couple of examples: let's say you have a unit with magic spring, duration 3, with three enemies around it, and you want to maximize mana received. If you attack, then you get a retaliation, and +5 mana, but now your magic spring will only have duration 1 left - 1 reduction from the retaliation, one from your unit ending it's turn. it will only be able to get an another +5 from magic spring. It may be better to wait with the unit, let the three enemies attack it, and receive all three +5 mana bonuses.

Let's say you have a unit with Magic Shield from Archmages in the middle of a group of enemies. Magic Shield only has duration 1 remaining. If you attack right away, the magic shield will help against the retaliation, but it will disappear after that and your unit will get pounded on by all the other enemies for full damage and suffer for the rest of the turn. If you wait with your unit and attack later, it'll have Magic Shield on it while all the enemies attack, saving you boatloads of damage.

Hypnosis works the same way. If hypnosis only has duration 1 left, it may be better to wait and soak up some damage before ending the unit's turn. This will also give you the flexibility to cast sacrifice later in the turn, as long as it's done before the unit ends its turn.