Most likely it’s because you’ll be lowering your average over the first few seconds as the resistance climbs from rest level to interval level.
As you didn’t post the power graph in your post, thought of asking, might there be a chance that you are using too big of a gear during the intervals for the watts needed. That may cause too much fluctuation in power, which in turn may lower the average watts.
it should not be the case as I am in ERG mode. Plus I was on small chainring and mid gear 
My Kickr 2016 is the same, i’m always 1W under
Makes me mad:)
This is the same for me too. I’ve got a 2016 KICKR, I’ve updated firmware, completed spindowns, tried changing gears, speeding or slowing my cadence and still I’m always -1% power output. It’s does my head in but I’m slowly learning to accept that’s how it is and I am hitting my numbers!
1W! ONE WATT. 0.5%. Power meters and trainers aren’t even that accurate 
It is all about Watts, even it is 1 
you all would go crazy if you were in resistance mode the whole time.
I have this same problem. Elite Direto in ERG mode. I usually increase the intensity by 1% whenever i can to balance this out. This sometimes increases the targets also, but i just go by the initial targets and make sure im hitting those.
The summary gives the average power during the interval, as measured. TR sends power changes 1-2 seconds early, to give reaction time to the trainer. Despite this, the trainer will probably be a little late hitting the target power at the start of the interval, but will also drop off from the target a second before the end. These two facts make the average slightly lower.
Here’s the beginning of an interval:
And the end of one:
That’s where your 1% goes. This said - do you think this difference has any impact on the efficiency of your training?
Might be losing perspective on why you’re doing this.
Da numbers!!! Da numbers!!!
Thank you for the info. “Da numbers” is totally on point. Its a psychological thing. I need to meet those targets in order to feel like I am applying self-discipline and not short-changing my workouts, regardless of whether there is actually an difference in training effect.
I just started with TR, currently in week 4 of ssbhv1. This is the first time ive ever done any structured athletic training, and hitting those numbers exactly or a bit over feels like what i need to do to keep myself on track. Maybe i’ll loosen up once i get some more experience?
Honestly, I never look at the summary. And by the way, the “missing 1%” ends up as an over-power on the recovery valleys.
Relax, do the workouts, don’t worry about the 1%. By the time you do 3x20mins threshold workouts, the behavior in the first and last second of each of those intervals will be the last thing on your mind.
