The coach won’t have any influence over FA results. The pre read could differ from the NPC but that would usually happen in atypical financial situations such as a family business. If your parents just have W2 income, don’t own a second house or business, and are confident they filled out the NPC correctly then it’s probably fairly accurate. The pre read will involve a FA officer actually looking at a complete application with tax returns and will give you a very accurate and reliable estimate.