I don't really understand your question but I'll give you my reasoning which will probably answer it:
To calculate the dps during the different buffs I divided the total damage that was dealt to the guardian (obtained by the difference in RG hp) by the time it took to deal the damage. So knowing that there were different phases (one with the channelling pylon, one with channelling and power, one with power and one without pylons).
So this wasn't done by theoretically calculating dps but by checking effective dps on the video. So all pylons were accounted for and that's why the dps seems weird: the barbs aren't doing 4 times their normal dps under the power pylon but only twice their normal dps. I don't know what is the cause of this and I'm actually trying different things on the PTR.
My first thought is that maybe the power pylon damage boost is additively stacking with the IK6 damage boost (I haven't been able to find a power pylon on the PTR yet and it's down for now so I'll try later).
My second thought is that maybe the damage bonus from the power pylon is stacking additively with the support's damage bonuses but if that was the case we would have seen it already on live servers and I've never heard of it. Maybe you could confirm this as you're a support and are more knowledgeable than me about this.