Can I slow down records that are played too quickly?

This can be done in the following way:

Set Stretch(%) = 100 * 100 / Pitch(%).

For example, if the pitch is 200%, set the stretch to 50%. If the pitch is 125%, set the stretch to 80%.
By doing so, you will reproduce the effect of changing the spinning speed of a record.

To specify pitch settings in percentage, use [Pitch by Percent] from the right click menu.
To specify stretch settings in percentage, go to [MASTER CONTROL] / [STRETCH] and input numerical values.