Shadow Priest Screams of the Void talent

Classes Priest
1

Hello, just looking for a bit of clarification on how this talent functions when using DP multiple times.

If I use DP again on a target within the 3 second window, does it refresh its effect to 3 seconds? Or does it stack (multiplicatively? additively?) and further increase the rate that VT and Pain tick?

2

I wish that it would last the duration of DP so that the talent that extends the duration would gain more value.

3

That would be very powerful, 80% hasted VT and Pain for the duration of a DP.

4

I get that, it’s just a cracked example of something that would make that DP talent more viable.