in alfa testing, there were exact numbers. they are changed to less likely, more likely... so the people need to find out best loctions on their own.
And digging is matter of luck. even if it would say 80 % instead of some word, that doesnt mean you will get 8/10. You could get 0,1,2...9,10. in average on big numbers, it will be 8/10, but you can get only 3 once, others can get 10 once. Like fliping the coin, its 50% chance to flip head, but that doesnt mean from 2 flips you will always flip 1 head.