When I built my PowerTap rear, I was raising the tension, then started noticing that it was going out of true. I tried to fix these spots by truing just with more tension (I was still trying to get the tension up a bit).

After I trued about two spots, I noticed that other areas were now WAY out of true. Then I realized that I must have gone beyond the rim's max tension. I spun the rim in the stand, and it was doing a 1" hula dance. F@ck.

Ok, so I backed off the tension, 1/4 turn at a time, all the way around. Sure enough, the rim went almost completely true. I evened the tension out from my previous truing attempts, and brought the rim back up to tension. I left it about 10kgf lower, and it came together fine.

I've ridden it about 2500 miles in four months, neither the true nor the tension have changed at all in that time. I believe the NDS is about +/- 3kgf on tension.

So, all is not lost. It will probably be fine.