...
The single-page complex form allows to fill in a large amount of mostly independentlarger amounts of data. The main characteristic of this form is to provide an instant overview over all key values. Its data sets are mostly independent of each other, but still connected data setsin the sense that they are part of a larger whole. While these data sets could be spread among multiple tabs, there's in your use case, you see a clear advantage to make all of them visible at once on one page.
In order to improve orientation in the form, data shall also be grouped visually. Each group of data must be consistent and constructed such that it may largely stand on its own. This type of form distinguishes In addition, we distinguish between important and less important data sets, the former being visible at all times while the latter may be hidden at first.
...
As stated in the goals, we distinguish between data sets , which contain containing values, which have to be entered every time or at least most of time a user fills out the form, and sets which are changed less frequently. We use a combination of field sets fieldsets to group important data sets and accordion-type tabs for hiding forms for less important data sets. Important data sets must be visible immediately when opening the form and may not be hidden by the user.
...
Do not use such a form, if your form actually does contain data sets, which are more like multiple, connected steps. In such a case, use a multi-step process. Also, if the overview over all values is less importantnot a requested feature, your form may be less overwhelming , if you break it up and make the parts accessible using tabs.