Possibility to choose whether an time based extra for a group booking should be multiplied by the number of persons or notcification#1660

I have a problem with the combination of group bookings and extras with time specification: I have a service that lasts 30 minutes and an extra “additional time” with which you can book an additional 30 minutes.
This works well with one person. A customer can therefore book the basic service of 30 minutes and, for example, book the extra twice, so that they receive this service for a total of 1.5 hours.
The problem with a group booking is that the time for the extra is ALWAYS multiplied by the number of people. So if two people book the same service with 2x extra, Trafft will reserve 2.5 hours for it. However, only 1.5 hours should be reserved. The time for the extra should NOT be multiplied by the number of people in my case.

It would be nice if there was an option to choose whether I want to multiply the number of persons with the extra time or not. It could work exactly like it works for the payment of extras. There I can choose if I want the extra to be multiplied by the number of persons or not.