All the particles will do it wear it more.
If you flush it being that high of mileage you could very well start a leak.
I would change the fluid, and filter. If it's burnt or brown it's not good.
Just so you know you may develope a leak.
I have never had a problem, I have never had a tranny flushed or done the fill, pump, fill thing. I just pull the pan, change filter, and put back together. It wouldn't hurt to change it again, by 30,000 or so if not before to help clean it out somemore.
I would drop the pan, change the filter, and do it again within the year.