If it's anything like in Awakening (and it should be), the random numbers are created long in advance, not at the time you perform an action. This means that if you execute the same chain of commands from a save that was made during a chapter, the results will be the same. Switch up the order or amount of actions and things will play out differently. Note that merely moving your units does not advance the random numbers, you'll have to enter battle.

As for the hit rates, the way they work in Fire Emblem is either via a single rolling number or two of them. I think that the developers have returned to a single number after Radiant Dawn. The random number generator uses the numbers from 0 to 99 and if the generated number is equal or higher than the predicted accuracy, then an attack misses.

(The dual-number generator made the predicted accuracy deceiving because it only held true at 0, 50 and 100%. But it favored strategic play, because it was deceiving in the sense that the actual accuracy was higher when above 50, and lower when below 50. That's why units in Radiant Dawn will hardly ever miss when the predicted accuracy is at 90%. Two random numbers from 0-99 were averaged, decimals were rounded up. If the result was equal or higher than the predicted accuracy, the attack would miss. Let's take 99% as predicted accuracy. With a single RNG, it was indeed a 99% chance (only the 99 of the RNG could make you miss). But with a dual RNG, there are only three combinations to make you miss: 99+99, 98+99, 99+98. Three out of 10,000 possible combinations. That means the actual accuracy was 99.97%.)

Sometimes you have bad luck and two of three enemies who have a hit rate of 33% land a hit, even though probability suggests that only one should succeed. At other times you are lucky and all three of them miss. Each attack gets its own random number, it isn't calculated in the sum.

It's also human nature that you perceive occasions where things work against you stronger than occasions where things play out in your favor.

If it's anything like in Awakening (and it should be), the random numbers are created long in advance, not at the time you perform an action. This means that if you execute the same chain of commands from a save that was made during a chapter, the results will be the same. Switch up the order or amount of actions and things will play out differently. Note that merely moving your units does not advance the random numbers, you'll have to enter battle.

As for the hit rates, the way they work in Fire Emblem is either via a single rolling number or two of them. I think that the developers have returned to a single number after Radiant Dawn. The random number generator uses the numbers from 0 to 99 and if the generated number is equal or higher than the predicted accuracy, then an attack misses.

(The dual-number generator made the predicted accuracy deceiving because it only held true at 0, 50 and 100%. But it favored strategic play, because it was deceiving in the sense that the actual accuracy was higher when above 50, and lower when below 50. That's why units in Radiant Dawn will hardly ever miss when the predicted accuracy is at 90%. Two random numbers from 0-99 were averaged, decimals were rounded up. If the result was equal or higher than the predicted accuracy, the attack would miss. Let's take 99% as predicted accuracy. With a single RNG, it was indeed a 99% chance (only the 99 of the RNG could make you miss). But with a dual RNG, there are only three combinations to make you miss: 99+99, 98+99, 99+98. Three out of 10,000 possible combinations. That means the actual accuracy was 99.97%.)

Sometimes you have bad luck and two of three enemies who have a hit rate of 33% land a hit, even though probability suggests that only one should succeed. At other times you are lucky and all three of them miss. Each attack gets its own random number, it isn't calculated in the sum.

It's also human nature that you perceive occasions where things work against you stronger than occasions where things play out in your favor.