so as I watch my crops have a cycle of 2-3 good increases on the Q's to 1 Great increase and then 1-2 decreases of said Q of crops. I thought about another formula that should be better overall. especially when considering the RNG.
the formula is the 3 crop qualities averaged then that number is then put against your farming score plus soil qualities averaged and the end result is in % to see if you get bonus positive numbers. this is done after the RNG takes place in order to counter effect negative numbers.(IE if you get a 100% chance for bonus points, there should be no negative RNG)
(example A) pumpkin 20/20/20 = average Q 20. farming score is 200 and soil 20/20/20 = 65. You have a 325% chance to get bonus points
(example B) Beet 190/190/190 = average Q 190 farming score is 200 and soil is 20/20/20 = 65. You have less than 1% chance to get bonus points, since its less than 1% and all percentages are rounded down, hence no chance for you.
hope this is not too confusing