With that being said, if you and your spouse have reached an agreement, the court will not scrutinize FL-150 for accuracy as long as the judicial officer feels that your agreement is fair. On the other hand, FL-150 is considered evidence as it is your personal declaration, so it never hurts to fill out the forms completely and accurately, since you never know what the future may hold.
Also, FL-142 is not filed with the court, but rather served to the opposing party.