If the Pendulum Scales of "D/D Savant Galilei" and "D/D Savant Kepler" have changed by their own effects and their Pendulum Effects are negated by "Spell Canceller", their Pendulum Scales return to their original values written on the card. After that, if the effect of "Spell Canceller" is no longer applied, their Pendulum Scales will start changing again during your Standby Phase, starting from the values written on the card.
Each time the "Once per turn, during your Standby Phases: Reduce this card's Pendulum Scales by 2 (min. 1), then destroy all monsters you control with a Level greater than or equal to this card's Pendulum Scales, except "D/D" monsters." effect resolves, this card's Pendulum Scales are reduced by 2.