The Five-Layer Task-Costing Pattern

Definition

An architecture separating task-cost concerns: facts at the bottom, derivations on top.

Worked Example

Layer 1  Estimates       - engineering estimates per task (immutable)
Layer 2  Actuals         - real costs from payroll, cloud, vendors
Layer 3  Variance views  - computed L1 vs L2 comparisons
Layer 4  Goal-task links - many-to-many with allocation weights
Layer 5  Goal budgets    - weighted roll-ups to the goal level

Interpretation & Pitfalls

Each layer has one job; upper layers are derived, lower layers are facts. The separation is what makes numbers trustworthy and analysis reproducible.

In TupicFinance

This pattern is implemented one-for-one: separate tables for L1/L2/L4, database views for L3, automatic roll-ups for L5.