Tried Cold Heart + Thief Ring combo with both a +10 knife and a +10 katar.
Only ASPD increase at 99 all stats (total, due to job level 1, though it does not seem to change much at job 70, and especially nowhere near the old bonus), apart from increase given from the +3 Agi given by the Cold Heart, was a +1 to flat ASPD.
At +8 refine and 99 all stats, it becomes a +0.
The script is actually for the refine rate of the weapon, divided by two.
However, players on other servers have also brought this up, and a lot seem to thing it is not a flat 5 (5, due to the script only being half of the max refine) ASPD increase at +10, or even a flat 5% ASPS increase to total ASPD, but only a 5% increase to a certain part of the ASPD formula.
The difference does become more apparent the lower your ASPD is. What is a 1 ASPD difference at 99 all stats a 2 diffence at 9 all stats, both at a +10 refine.
At 1 allstats, it is a 3 ASPD difference.
An admin on another server posted this in explanation:
Aoi Wrote:
WD: Weapon Delay
SM: Speed Modifier
Ex: Assassin with 100 AGI and 1 DEX using one dagger. No SM.
ASPD: 200 - 29.9 * 1 = 170.1
Ex 2: Assassin with 100 AGI and 1 DEX using one dagger. 5% SM.
ASPD: 200 - 29.9 * 0.95 = 171.595
The reason you don't see much of a change with 5% ASPD increase is because you're not changing the ASPD you see in the status window by 5%, you're changing part of the formula. In this case the 5% is only affecting the number 29.9.
This also means that with more AGI and DEX, 5% increase becomes worse than before. With high AGI and DEX, the number 29.9 would be even lower.
These results don't seem to show exactly what the ingame status window is showing, but it should at least explain why 5% doesn't really show up.
As to how accurate it is, I can't personally atest to. I do know, however, through my own testing, that the lower the original ASPD, the more of a bonus you get, but at no stage does it reach the 5 flat increase(remember, item script is refinerateoftherigthhand/2) that people expect, nor the 10 flat increase that used to be experienced by players.
Edit: Ex-GM Ayu informs me the our last SVN's item script was made by her, to her interpretation of the description at that point in time, and it is safe to say that the combo effect of this SVN is now the official one.