Blacker than Black
These are my derivations from and clarifications of 6th ed. Call of Cthulhu rules.
Round only after all multiplication, division, addition, and subtraction are finished, and round normally.
Luck = 2.5 x (INT + APP)
SAN stat on the character sheet is the max that can be achieved through therapy and rest. This is still limited by 99 – Cthulhu Mythos. Achieving adventure and campaign goals as well as defeating horrors can raise your current sanity above this value.