Thank You for your anwer.
I think there is a small problem with the code, the following line gives an error:
tmp = serie.data[point.x].series.name + ': ' + point.y + 'm';
Cannot read property 'series' of undefined
I think it should be:
tmp = serie.data[i].series.name + ': ' + point.y + 'm';
Now the series names are correct, they get bolded as expected, but both values are the same which is not correct:

I will be grateful for solving this problem.