In common terms it is about the Support and Resistance Lines, but in PFT it is wider and refers to the reliability of the micro (local) graphical model.
Example: scale 3 shows us sharp Amplitude Increase but lower tangent became unreliable and can’t be Support Line (and market confirms it by easily penetration through that line). But at scale 4 lower tangent is more reliable and may be a boundary of the real channel.
In general words, the last tangent in configurations with Amplitude Increase can’t be a good estimation for the channel.
SG-Анализ (SG-Analysis / PF-Analysis) 