How determininstic is Metal Slug?

There are bonuses in the Metal Slug games that can change value wildly (e.g. from 30000 to 100), in an apparently random fashion.

I have the impression that at least some of them aren't completely casual: for example at the boss of mission 1 in Metal Slug 3 after following the submarine path, there are two POWs that give a bird nest which can be valued either 30000 or 1000: I have the impression that if you grab them closer to the boss and without shooting, you have a higher chance to get the better score.

I came across also this video, in which the player manages to max out all the random bonuses: I am aware that if the PRNG is queried/seeded continuously each frame it might be possible to cheat it by trying many times from the same save state until you get the best outcome, but I'm not sure whether that is what happened there.

So, my question is: is there any known logic in the value of the variable bonuses?