alexandre.vidual,
Extrapolating the PC1 chart shows that increasing the TDP/Vtoss by 1-kt (above the limit) would produce 26,500 lb at sea level 34˚C, but you obviously can’t exceed the TDP/Vtoss limit. I think the 2˚C difference is between the PC1 chart and the first segment climb chart, and I assume that is a function of nomogram format chart and graphical interpolation precision.
HT