Sworn translations always require more work, and therefore more time, from the translator. Even more than elsewhere, every letter is checked, also in terms of layout. You can never translate authentic documents using a translation memory, which can otherwise speed up the task.
In addition, both source and target text must always be printed to be able to stamp and sign on the back, and usually additional agreements regarding delivery and service are involved.
Finally, sworn translators and interpreters are required to keep their legal knowledge up-to-date through training courses that also require extra time and budget; otherwise they will lose their title.