lose the plot vs overbalance

lose the plot

verb
  • Used other than figuratively or idiomatically: see lose, plot. 

  • To lose sight of an important objective or principle; to act contrarily to one's own interests through concentrating on relatively unimportant matters. 

  • To cease to behave in a consistent and/or rational manner. 

overbalance

verb
  • To lose one's balance; to fall over. 

  • To throw (someone or something) off balance; to cause to capsize. 

  • To be more important than; to outweigh. 

  • To cause an imbalance in (something) by means of excess weight or numbers. 

noun
  • Excess of weight or value; something more than an equivalent. 

How often have the words lose the plot and overbalance occurred in a corpus of books? (source: Google Ngram Viewer )