So, you would be less likely to hit full speed - and it being max speed drill/exercise, the exercise become mute? ie, practicing max speed drills at sub max speed.
I would be more akin to using split 60’s for the purpose of what you’re after.
Or, cut the Max speed component - ie, 25m lead in, 10m Fast, 25 lead out - That is, if you want to cut the intensity of the total effort, yet still focus on Max speed.