Previously, the Marlin simulation used default values for jerk and max acceleration. With this release, jerk and max acceleration are read from the printer to make the simulation even more accurate. If you modified the analyzer list previously, you may need to reset the analyzers. There is a button for that.
You can also see a table of estimated vs actual print times in the settings now.
Thanks to everyone that reported issues. Please send more bug reports and also CSV output if you can get it so that I can measure the simulation accuracy.