Capital Gains Estimator not finding lowest tax solution, way off from best?

DeVille63

I am using the capital gains estimator to "Minimize taxes and commissions but keep things simple" for $100,000 proceeds. However, the estimator is not finding the best solution. The best I can get is a $15,000 capital gain using the estimator vs a $1000 capital gain using an Excel spreadsheet and sorting on the tax lots with the lowest % gain. I tried various search settings and customize parameters, as well as adjusting the short & long term capital gains tax rates. Any suggestions?