I understand if it fail to record a runner's time because it might have failed to give a signal. But
it does not make sense if the recorded times are
off by certain amounts.  I think what is new here is
just the chip. The mat and other stuff should be the
same as old ones.  If a time is recorded, then the
signal must be received. Then what can account for 
the off amount? Processing of the signal get jammed?