Effect of size?

[Akynos]

Hey guys, just a quick question regarding size - I just changed one of my achievement slots from +5 Stamina to +5 Size, expecting it to make a proper difference. However I went from 1362 to 1368HP and the encumbrance didn't even decrease by a percent.
Now did I miss something or is size not really effective? Because as it stands I've gained 6HP and lost 5 endurance points, which as a tank is quite a nasty tradeoff.

Thanks !

[weaw]

Some Achievement moves:

Total Equipment Weight: 61.0.
191 STR, 144 STA, 65 Size: 34% Encumbrance.
191 STR, 144 STA, 75 Size: 30% E.
181 STR, 144 STA, 75 Size: 30% E.
181 STR, 134 STA, 75 Size: 30% E.

Total Equipment Weight: 60.2.
214 STR, 135 STA, 114 Size: 19% E.
214 STR, 135 STA, 104 Size: 21% E.
214 STR, 125 STA, 104 Size: 22% E.

Some conclusions:

-- Stamina affects Encumbrance;
-- The higher the relative change of Size , the better effect.

Assumption:

-- It's almost obvious: The higher the Total Equipment Weight, the smaller effect.