The suggestion is based on how close the pick up address is to the taxi company’s base. What’s considered the taxi company’s base is the geographical center of the service area you created for your company profile. You can configure how you want the system to calculate this by setting the time/distance variable yourself. For example, if you want it to calculate that a kilometer takes 2 minutes to drive instead of the 1.5 minutes set by default, you can do this by going to Settings > Dispatch > 2. Assignment > Dispatch timings > Time per km, here: https://admin.taxicaller.net/admin/settings/dispatch.php#company_tab_assignment
The system then looks at how far away from the company’s base the pick up location is and applies this variable to it to suggest the assignment time. It’s important to note that a dispatcher of course also can select a different assignment time from the list themselves.