GoogleBot does not follow normal time. This page identifies that the Date.Now and performance.now functions always increment by 1ms, but does not take into account real time spent processing (the delays).
performance.now has a higher elapsed time as it's start time is a little earlier that my Date.Now start time which is set when the first JavaScript runs.
Each function independently increments 1ms each time they are called. However they
Testing in a normal browser does not see these increments, but does record the delay times.