question

The pick time you are getting is not actually negative. If you extend the width of the PickTime column you will see the entries actually read "01-01-1601 00:00:XX". This is because you set the column to display in Date/Time format.

This will interpret the value as the number of seconds that have elapsed since midnight on the 01-01-1601 and display the resulting date and time of day. If you want to display the time in this format, the way to get the correct value is to use "Model.dateTime".

The PickTime in the tutorial represents a timeframe though and not a single point in time, so you want the value (time that elapsed between the first and second event in the statistics collector) to be displayed "Raw". By default, the unit will be seconds. This can be changed in the popup window when creating a new model.