A "normal" distillation column has a reboiler, so that the bottoms temperature is higher than the feed temperature, and corresponds with the boiling point of bottoms product at the bottoms temperature.
In a crude oil fractionator that is not the case, due to the stripping steam. The bottoms temperature is lower than the feed temperature, due to loss of heat of vaporization as result of steam stripping of gasoil components. Less steam stripping would result in higher bottoms temperature as less gasoil would be vaporized.
Less stripping steam in the column overhead, while still producing the same quantity of overhead naphtha product (so same TBP cutpoint) would result in higher overhead temperature, because hydrocarbon partial pressure would be higher. If however the reflux is on temperature control of column tray temperature, and the setpoint of that TC is not changed when stripping steam is reduced, the TBP cutpoint of the overhead naphtha would change, and it becomes a different story.