When a stair stringer bears on a ledger or a landing and is notched there, the board's shear capacity drops much faster than the lost depth suggests. The framing takeoff's stringerCheck now takes notchedSupport (true to use the throat as the depth left, or the inches left) and compares the end reaction with (2/3) Fv b dn (dn/d), the notched-member form in the NDS for a tension-face notch, where d is the board depth. You type Fv; nothing is shipped.
Hand arithmetic, as in the tests: a 9-1/4 in board with 5 in left, 1.5 in thick, Fv 180 psi, allows 486.5 lb against a 277.8 lb reaction, so it passes. Leave 3 in and the allowance falls to 175.1 lb, and the check warns to keep full depth at the bearing or hang the stringer.
Not covered: notch radius, the engineer of record's call, and any real stair.