There is a bug in the retractation filament distance. The gcode uses the value of "Tool change retraction distance" (Advanced), instead of "Retraction distance" (Extrude).
For printing with 1 material this 2 values must be same, but for printing with 2 materials, the "Tool change retraction distance" is used even when there is not tool change. That increases significantly the printing time because it is much more important to prevent filament heating during the wait.
This problem is it identified?
(Thanks for your good job on version 3)