it is does not matter, what to insert in the "hour" field: "12", "12h", "12 h" or "-12 days", in any case it will be treated as "12h" (analogous for the other fields);
in the upper field: "yesterday" will be "1" (or "-1"), "the day before yesterday" - "2";
it is impossible to estimate precision before estimation of the growth time;
Equations.
For bacteria in the logarithmic stage of growth:
OD1 = A * exp{k(t1 - t0)}
OD2 = A * exp{k(t2 - t0)}
ODf = A * exp{k(tf - t0)}