Not quite. Let's look at two scenarios I actually have experienced in the past testing the pseudorandom numbers from it when I figured out how the system worked (from what I experimented with).

Say you have Soldiers A, B and Aliens A, B.

Scenario:

Before first move, say, p-random numbers generated were 43, 97, 82, 22, 67, 03, and 42.

(I don't know the actual formula, so I suggest we go by the method of a simple 0-100 percent and you have to roll below that number to hit....e.g. 65% chance to hit = 1-65 hit, 66-100 fail.)

Soldier A moves to flank Alien B with a 65% chance of success. SA shoots and hits, since the pre-rolled 43 is within the range of success.

Next, Soldier B moves to assist SA, flanking AA, with an 95% chance to hit. Since the next number generated was 97, he misses.

Alien A, still alive moves right up to SA and with an 85% chance rolls an 82 and blows away SA. Alien B now moves to Soldier B and hits with a 35% chance of success by getting the 'pre-rolled' 22.

Shitty move, right? Well, let's try to modify that.

We reload the save, and instead of following the exact same movements, we alter a couple and get completely different results...not because it's random, it's because the same sequence of numbers are used, but appear to be not thrown away and used whenever the next call for it is.

Soldier A shoots the alien as normal, but SB now hunkers down instead, passing the 97 to AA. Alien A misses a 95% shot due to using the 97 that SB skipped, and now that both soldiers are still alive, AB moves back away and shoots from a distance, missing their 20% shot by rolling the 82, and you get the idea.

Once I saw the pattern, I started testing it a lot and this is what I figured out. I'm not saying it works exactly this way, but the scenarios I experienced and tested seemed to match this pattern.