I'm really bad at hacking, but I've noticed resources at 0 are counted as 64. 18 is counted as 50, a decrement of 3 becomes 46 (-4), another decrement of 3 becomes 40 (-6).
I don't understand it at all, I just search for 64 (for a reasource I don't have), then Unknown/Decreased until I find it. Otherwise I just get 18 of them, search for 50, then decreased/increased as I use them in a station and then cancel the build and do that over and over again until I find it. Increasing it from 50 to 255 gives you 126978 as a value.
You can also clearly see that when switching the value from 255 back to 50, it returns 18.00.
Maybe someone with a stronger math brain than me can figure out the correlation between these values and understand how it works.