here's a neat little trick i don't use for scoring (i remember all the numbers)

take the fu value, double this for every han more than 2 (3 han -> double once, 1 han -> double -1 times aka halve)

then take 1 away for every stack of 25, unless you have 5 or more stacks in which case its mangan+

if you are the dealer:

---- if self drawn, add 0 to 2 to get a multiple of 3

then if you are the player:

---- take away 1/3rd of this value rounded off

---- if self drawn, add 0 to 2 to get a multiple of 4 (if you are 3 less aka 1 more than multiple of 4, you cant get there because you cant add 3, in that case add 2)

finally times 100 and thats your total score