Not sure if the question is correct.
How much different is the ball speed or rotor speed, it changes everything?
The question is in VB section; it may be tilted wheel, some changes in ball speed may almost have no change on the result. Roulette rotor speed always has changed to the result but again the question is how much and how far to the end. You may have 5s to the end of spin and rotor 1p/s faster making it only five pockets shift to the final result, where the ball drops. On the other side, a small change on the ball may result in significantly different result regardless of how far from the end of spin you measure it.
If you look in percentage as 10% of the change in the ball speed definitely will make a greater difference than the 10% change on the rotor speed, if the measurement is within prediction limit time to the end of the spin.