This indicates that those (traditions indicating long surahs) are abrogated, and this is more sound tradition. (Using translation from Abū Dāʾūd 813)
أَنَّ أَبَاهُ كَانَ يَقْرَأُ فِي صَلَاةِ الْمَغْرِبِ بِنَحْوٍ مِمَّا يَقْرَءُونَ وَالْعَادِيَاتِ وَنَحْوِهَا مِنَ السُّوَرِ