Co-owners frequently sign a written agreement at acquisition—spelling out contribution percentages, reimbursement waterfalls, or buyout terms—and then later record a deed that says something simpler, like joint tenancy with equal shares. When the relationship ends, one side argues the deed superseded the agreement; the other argues the agreement still governs. Whether it does is a legal question. What the parties actually did is a financial one, and that's where the ledger becomes evidence.
Post-deed conduct leaves a paper trail: payments made in agreement-consistent proportions, reimbursements that track the agreement's formula, references to the agreement in emails accompanying transfers. A refund or true-up payment made after the deed, in an amount only explicable by the agreement's terms, is worth more than a stack of recollections. Conversely, if conduct changed sharply at the deed date, that pattern shows up too.
The forensic deliverable here is a conduct timeline: every financial event after the disputed instrument, plotted against what each document would have predicted. Counsel argues what it means; the timeline makes sure the argument rests on dates and dollars rather than dueling memories.