Assassinate with Shadow Partner

Assassinate has 5 stages depending on the charge time. In the beginning of every stage, Assassinate increases its damage by 100%, and somehow it applies to Shadow Partner as well. For Shadow Partner it goes from 50% --> 100% --> 150% --> 200% --> 250%.

I'll put it in a chart so you can understand easier :

Charge Time | Assassinate | Shadow Partner
0 ~ 1 | A * 100% | 50%
2 ~ 3 | A * 200% | 100%
4 ~ 5 | A * 300% | 150%
6 ~ 7 | A * 400% | 200%
8 ~ 8 | A * 500% | 250%

Where A is your Assassinate's damage without charging.

And yes, if you only charge for 2 or 3 seconds, your SP's damage = Assassinate's damage: link