Weapon cooldown on pickaxes is offset with linear functions

When weapon cooldown was added, I tested it with all tools and weapons and recordd theire linear values on a plot. On beforehand calculatens I had values i expected, but testing shows that pickaxes functions are offset of the theretecal values, which are based of of attackspeed, attackdamage, and damage pre second. i determend it was a hiden value.

Plot:
V: expected value
U: actual value

decresing attack speed ----> decresing DPs ⬇

DVDDUDDDDDDDDDDDDDDDDDDDDDD
DDDVDUDDDDDDDDDDDDDDDDDDDDD
DDVDDDDUDDDDDDDDDDDDDDDDDDD
DDDDDDVDDDUDDDDDDDDDDDDDDDD
DDVDDDDDUDDDDDDDDDDDDDDDDDD

reproduce:
1. get all types of pickaxe,
2. compare values and actual results
3. notice there is more delay in the linear functen caused by a unexpected value, making longer cooldown.