How is duration affected?

IIRC, Hour of Power is weaker than casting all buffs separately, it simply saves quite a time by casting all those buffs in one big batch.

I remember Haste was always an issue, because its duration was much smaller than from standard Haste spell, so it was better to recast Haste after casting Hour of Power. When Haste runs out, your characters become weakened, and it adds additional hassle.

Other than that: Day of the Gods + Day of Protection + Hour of Power, and your characters become powerhouses :) Well, almost.

Ok... looks like the spell does not specified that it only affects the duration of them...

Any spell that has an X amount tied to the skill, is always your skill in Light Magic no matter the expertise on it.

Looks like Hour of Power, Day of Protection and Day of the Gods only affects their skill duration and not the skill amount of "effectiveness" of the spell included in those packages.

Maybe Im reading into this all wrong...
The only thing affected are what is written in each of those Normal, Expert, Master description of those spells.
M'bad.

Hmmm, my experience was exactly the opposite. Hour of Power lasted way longer and was particularly convenient for Haste, which if cast by itself ended too quickly. Was it because you had less Light skill that you had elemental, spirit... etc? Or maybe it was changed from MM6 to 7. I don't recall using Hour of Power in MM6, but in 7 used it a lot.

Just loaded my MM7 game.

HASTE:

Haste cast by mage (16 Fire Magic GM) - duration 2 hr 4 mins
That's 1hr + (4min x skill)

Hour of Power by cleric (16 Light Magic GM) - duration 6 hr 20 mins
Hour of Power by mage (17 Light Magic GM) - duration 6 hr 40 mins
That's 1hr + (4min x 5 x skill)

BLESS EFFECTS

Bless cast by Cleric (15 Spirit GM) - 20 bonus
5 + skill

Hour of Power by cleric (16 Light Magic GM) - 21 bonus
Hour of Power by mage (17 Light Magic GM) - 22 bonus
5 + skill

BLESS DURATION

Bless cast by Cleric (15 Spirit GM) - 16 hrs
1 + (1hr x skill)

Hour of Power by cleric (16 Light Magic GM) - 20 hrs
Hour of Power by mage (17 Light Magic GM) - 20 hrs 15 mins
(1hr15 mins x skill)

So by the looks of it, the HoP spells behave differently. Haste duration is indeed calculated at 5 times Light magic, however for Bless, effect is calculated at base light magic, while its duration is only slightly larger, (by a factor of 1.25 minus that extra hour that Bless gets if cast separately).

Maybe the devs saw that casting them all at 5x light magic was overpowered so they nerfed some of the spells?

This is MM7. Could have been different for MM6.

It seems I remember things wrong. And I just relaunched MM 6 with my Lv.100+ characters.

Light Magic Master 10 - Hour of Power:
- Duration of all spells (except Haste): 16h 3m
- Duration of Haste: 4h 3m
- Benefit from Bless: +20

Spirit Magic Master 8:
- Benefit from Bless: +17

Fire Magic Master 23:
- Duration of Haste: 2h 45m

I feel shame, I should have checked it first >.<

Actually, this doesn't seem to be the case. I just checked. Subspells included in the Day of the Gods spell are more effective at Master Light rank than at Master Spirit/Mind/Body rank: at Master Light, the buff is 10 + 4 points per skill at Light Rank, as opposed to 10 +3 points per skill at Spirit/Mind/Body. The effect of Haste is the same, but with the longer duration. The effect on heroism is identical (5 + per skill). All figures are for Master Light, and I haven't checked for Expert rank, but ultimately there seems to be no reason to pump skills into Spirit beyond 4 - Master if you have a Light spellcaster.