For each mobile number, you see how much traffic (Voice & Data) was generated in each zone (Swiss / Neighbours / Europe / Global / GlobalPlus) and how much that traffic was charged in case it wasn’t included in the subscription.
With such information, it becomes easy to identify mobiles where the subscription should be upgraded or downgraded.
In this screenshot, we see the highlighted mobile has a “Global” subscription but generated almost no traffic in the regions Neighbours, Europe and Global over the 4 months displayed. We can safely downgrade to “Swiss” and save around 150.- CHF/month (depends on your contract). If the mobile still generates some traffic in Neighbours, Europe or Global, that traffic will be charged but it will still be more convenient than paying each month for a “Global” subscription.