You can add survey questions, plain text screens, etc anywhere during the ACBC questions.
However, you cannot change the conjoint attribute list (the list of attributes and levels per attribute) once you've started the BYO questions. So, you'll need to do this in the way you say you've done before. But, for the interest of others who might be reading this post...
When researchers want to have the respondent screen the top n most important attributes and use those attributes within the ACBC survey, the typical procedure is:
1) Introduce the respondents to the full list of attributes and ask the respondent to indicate their top n attributes that affect their choice. This question can be asked as a Select question or a drag-and-drop sorting question. (Often, price is not asked about in this question; but is always forced into the ACBC section).
Based on the responses to this preliminary question, only the attributes of most importance are moved onto the constructed list of attributes used in the ACBC exercise.
2) Ask the ACBC BYO question, only of the attributes of most importance as learned from the previous Select or sorting question.
3) Ask the ACBC Screeners section.
4) Ask the ACBC Tournament section.
5) (Optionally) ask the ACBC Calibration Concepts section.