Also, relative to the amount you get paid. If you can figure out an easy way that shows you didn't pull it out of the air then you won't be ever asked again. I normally only have a couple adjustments in my big urban area. So for bathroom i comment on cost new &15,000 minus any depreciation and/or floor location influence. We have baths in finished basements here and in finished sheds. It's all row homes. Now you never have to go any further comments, your adjustment on the grid speaks for itself. You can say that for any physical piece.
Look for the GLA excell chart on this blog. It actually works well most of the time, you can adjust it. The chart looks good in the report. And have a separate page called adjustments to make it easier to find and read.
You idea is to show that you gave it thought, without having to show pages of calculations. I have never been asked what you have been asked. Make yourself smarter than the average dope you have to compete against. My appraisal is literally my work file.