Function tolerance 

fn tolerance(flows: &[Flow], needed: Money) -> i64

“As planned” within this many cents of the target, the same for sioul budgets (status) and the window’s verdict (pace): 5 % of what the period moves (each of its flows, in or out, done or planned, and what it still needed beyond what is scheduled), never closer than 10 units (docs/accounting.md, “On track, without assuming money flows evenly”). Wide enough that a budget whose money comes later in the month is not “short” in its first days.