Frozen Fury & Boast +1[w]... am I missing something?

[Thunder-Monkey]

So Warchanter's Frozen Fury (rank 2/3) & Boast both claim +1[w]. I thought it would be safe to assume they would have the same effect on damage as Cleave's +1[w], but after testing, i'm not so sure.... am I missing something here? are there some game mechanics I haven't considered?

TEST CONDITIONS:

1. Test was 50 swings at training dummy per pass. 3 passes of each attack were made and the middle scores are shown. Parity was shown in all passes of each attack.
2. Avg Dmg is the mean dmg of those 50 swings
3. 'Misses' were not counted, nor were glancing blows
4. Weapon used: Antique Greataxe (not epic) 1[w] adamantine (to bypass the dr on frozen fury)
5. No buffs, power attack off
6. Dummy was reset on each pass and was never made 'helpless'
7. The Frozen effect was allowed to expire between attacks

RESULTS:

Base Dmg (normal swings x50)
Total Dmg: 1204
Avg Dmg: 24.08

Cleave x50
Total Dmg: 1893
Avg Dmg: 37.86
Dmg Increase: +57.23%

Frozen Fury x50
Total Dmg: 1566
Avg Dmg: 31.32
Dmg Increase: +30.07%

x50 Normal Swings with Boast
Total Dmg: 1533
Avg Dmg: 30.66
Dmg Increase: +27.33%

As you can see the numbers aren't what I was expecting. What did I miss???