Yes to both questions.
There actually is a "play value" command that lets you set the actual playback multiplier based on values that are included in the script, described here:
http://www.e-Valid.com/Products/Documentation.9/Commands/playvalue.htmlTo vary the playback times in your script you may wish to use the WaitUniform command, which will let you impose a variable wait time uniformly distributed between any specified lo-value and a hi-value.
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The eValid Support Team