Have not been much playing lately, but this weekend I finally got some chance to run a larger 4.5 Edition battle. I thought I would take the opportunity to check the outcome of this battle vs. my own 4.5 Edition simulations. The group consist of 6 characters, all 9th level. They faced a 10th level encounter. The encounter was built in two waves. The first wave was 3 goblins (level 1 skirmisher), 3 worgs (level 3 brute), 1 troll (level 9 brute), and 8 goblins (level 2 minion). The second wave was 5 orcs (level 6 brute), 1 orc (level 8 controller), and 1 drake (level 3 artillery). In 4th Edition this would be an EL 5.7 (1398 XP) first wave + an EL 6.9 (1750 XP) second wave for a total challenge of EL 10.2 (3148 XP). Under my 4.5 Edition rules it is EL 7.8 (4996 XP) + EL 6.6 (3770 XP) = EL 10.2 (8766 XP). Please note the difference in which Wave is considered the hardest in the two editions - the second wave in 4th and the first wave in 4.5.
Based on this I can set certain expectations on the battle based on the 4.5 Edition Encounter Building guidelines (page 12). Three of these encounters should be a full adventuring day, and by the end of the day the party should have Full HP and only 80% of their total Healing Surges left. The battle should on average take 4.7 rounds to resolve. So what was the real outcome?
This is how the party resources looked like after the battle – [remaining (original)]:
Druid – HP 60 (60), HS 10 (10), Daily 2 (3), Healing Word 0 (2)
Ranger – HP 57 (57), HS 7 (7), Daily 2 (3), Healing 1 (1)
Wizard – HP 54 (54), HS 8 (8), Daily 1 (3), Healing 0 (0)
Fighter – HP 35 (66), HS 11 (14), Daily 0 (3), Healing 1 (1)
Rogue – HP 58 (58), HS 8 (8), Daily 1 (3), Healing 0 (1)
Barbarian – HP 6 (64), HS 5 (10), Daily 2 (3), Healing 0 (1)
Total – HP in HS value 28 (36), HS 49 (57), Daily 8 (18), Healing 2 (4), Healing Word 0 (2)
If we look at what the Encounter Building guidelines would indicate, it would be:
=> HS: Used healing surges during the battle would be 57 * 0,8 / 3 = 15.2 HS per encounter
=> Daily: 18 / 3 = 6 per encounter
=> Healing: 2 Healing Words + 4/3=1.33 Healing used per encounter
=> Time: 4.7 Rounds
So what was the actual outcome in comparison:
=> HS: 8 HS lost (in lowered HP) + HS 8 lost = 16 HS lost of 93 HS. This is well in line with the expected 15.2 HS per encounter in the guidelines
=> Daily: 10 was used, which is 4 more than the anticipated 6
=> Healing: All Healing Word used and 2 Healing used, which was 0.66 more than the anticipated 1.33.
=> The battle was resolved in 6 rounds, a little more than the expected 4.7 rounds, but this might be due to the "2 Waves" setup with a lost round for transportation for melee combatants.
Conclusion: At least for 9th level the Encounter Building and the XP system seems to be quite well tuned, and allows for good DM control when planning the encounters. The ability to be able to break up the adventuring day from 3 to up to 9 encounters is also a flexibility that helps when converting adventures or creating new ones.