The values of the elapsed time between an Original SQL and Best Alternative in the Report Comparison tool have incorrect values.
The issue is consistent across optimizations of dramatically different queries. An example is in the Total Elapsed Time and Execution CPU Time; the Time Saved(%) is equal to 1.0 minus the percentage shown in the chart attached. But for Execution Elapsed Time, the Time Saved(%) has no obvious relationship to the actual data, and neither does the Times of Improvement.
Waiting for a fix in a future release of SQL Optimizer for SQL Server.