The main part of a water change is to remove excess nutrients...since you don't have any livestock yet there won't be a huge amount of excess.
I'd be concerned about those high nitrate levels - assuming the tests are accurate. @ 160ppm a 10% change will drop those to 144 ppm, so not as effective as one would hope.
I'm in the "use ammonia" group. In a typical setup you would never get a positive ammonia test - it's the low hanging fruit in the energy chain we call the cycle. While not likely to get a positive nitrite either, it's more likely shortly after feeding just because of an abundance of "stuff".
when there is nothing in the tank but hope and plans dosing ammonia is the end result of feeding. it's quite harmless. it's best practice to stay south of 2ppm though. to much of a good thing can slow down and even reverse your good work. like disinfecting your laundry.
Since you added to 2ppm and it was consumed in hours you can be sure that things are working as they should. I'd likely continue but with this caution - use ¼ of what you did for 2ppm.
But definitely be sure of your nitrate level before bringing things home.