Good morning dear community

I have a doubt about the limit for the charge density in the graphs for sigma-profile or sigma-potential. Some articles I read say that this limit for the change of polarity in the molecules is ± 0.01(e/Å2), others say ± 0.086 (e/Å2), others 0.08 (e/Å2). Is critical this difference? What is the real value that I should use? Thank you for the clarifications in advance. Best regards.