Split came when the severe economic difficulties strike. No question Liu, Deng supported the program initially. Before the economic calamity Deng said the success is yours, the Secretariat will take the blame if it failed.
主张中国原子弹下马 during the difficult years was just a matter of difference of opinion and strategic insight. There is no need to dwell on the subject. I have bigger issues to find with Liu and Deng.