Cells L20 to R93 contain the by-rail Peak / PDN estimate. This estimate is
derived from the entered use case.
Column R creates a label
V_G1 through V_G18 (e.g. voltage group.) These labels can be modified by
the user.
The same labels are present in cells P2-P19. If the user modifies the
labels in column R, the labels can also be modified in this range. Cells
Q2-Q19 sum the current for this voltage group.