Custom duration Addon

Hey guys,
I’m using Bookly + the Custom Duration add-on. In the classic step-by-step form shortcode [bookly-form] I can hide fields like categories/services/staff/date/time_range via hide="...", but the Custom Duration dropdown (service duration / units) still shows.

Is it correct that the classic [bookly-form] shortcode cannot hide the duration/units field via hide="units" or hide="duration"?
If so, what’s the recommended way to:

1. i have 5 services. 4 with costum duration - 1 without and there i have to hide that duration drop down.

2. hide the duration dropdown on one specific page (e.g. Page ID 63)? Thats not realy cool couse i have to klick to see my timeslots.

Thank you for your help,
Thom