It's pretty simple... 60 = 1:00 so adding 60 SECONDS with 60 SECONDS will equal out to 2 full minutes. I think she has this mind-set: 60 + 60 = 120 but not in seconds, just 60 + 60.
Not only are the trains now running on time, they're running on metric time. Remember this time people, 80 past 2 on April 47th, it's the dawn of a new enlightenment.
Although when inputting time on a microwave, it does sort of bother me that typing in '99' gets you ninety-nine seconds, but typing in '100' gets you one minute. I feel the system is confusing, poor math aside.