The help of minutes tells us
If X is a numeric array, then M is a duration array in units of minutes.
If X is a duration array, then M is a double array with each element equal to the number of minutes in the corresponding element of X.
so
minutes(seconds(1))
and
minutes(seconds(200)
give a double, while
minutes(1)
gives a duration. So you have
<double>:<duration>:<double>
which messes all up. To increment by 1 minute, use
minutes(seconds(1)):minutes(seconds(200))
