IF vs events in gs_design_ahr and gs_power_ahr

[yuliasidi]

Is there a reason for using IF argument in gs_design_ahr vs events in gs_power_ahr? If not, I would recommend using the same argument in these two functions for consistency

[nanxstats]

+1. On the big picture, we will definitely need a consistent glossary for all the design software we want to build.