For hair color appointments, we would like to use Add-Ons to add haircuts; and use Modifiers for long/thick hair, conditioning treatments, etc.

However, whenever Modifiers are selected, the Add-on service gets bumped to the top of the list of services. So the system schedules the haircut first then the color and modifiers. If no Modifiers are chosen, the Add-On is added correctly, after the base service.

Can this be changed so that the Add-On service is always scheduled after the base service, regardless of whether Modifiers are selected?

It works perfectly when we do in-house scheduling. It is only a problem with online booking.