Estimation Sections

Estimation Sections provide a way to organize an estimate into logical work categories, each with its own margin structure. Instead of applying a single profit margin to the entire estimate, sections allow differentiated margins per cost type — enabling more accurate pricing for different kinds of work within the same project.

What an Estimation Section Is

An Estimation Section is a named grouping of estimation lines (modules, materials, labor, expenses) within a project estimate. Each section carries its own margin configuration, independent of other sections and of the estimate-level defaults.

A default section is created automatically when a new estimate is created, ensuring every line belongs to a section.

Section Margins

Each section supports differentiated margins across three cost types:

Cost Type	Description
Material	Margin applied to material costs within the section
Labor	Margin applied to labor costs within the section
Expense	Margin applied to expense costs (subcontract resolves through expense margin)

Margins are resolved in order of precedence:

Line override — an individual estimation line can override the section margin
Section margin — the section-level margin for the cost type
Estimation default — the estimate-level default profit margin (fallback)

Module child lines follow their parent module’s section — they cannot be reassigned or overridden independently of the module.

Margin Basis

Sections support two margin calculation bases:

Basis	Formula	Meaning
Markup on Cost	`price = cost × (1 + margin%)`	Margin is a percentage added to the base cost
Margin on Price	`price = cost / (1 - margin%)`	Margin is a percentage of the final price

The margin basis can be set at the estimate level or overridden per section. Margin-on-price values at or above 100% are rejected.

Display Mode

Estimates can present pricing in two display modes:

Mode	Description
Differentiated	Each section displays its own margins and subtotals
Blended	Sections are aggregated into a single blended margin for presentation

Switching display mode does not change the stored margin values — it only controls presentation.

Expense Pricing Mode

Beyond the section display mode, each individual expense line can be priced in one of two ways:

Mode	Meaning
Standard	The expense is priced from its quantity and unit cost
Lump Sum	The expense contributes a fixed lump-sum amount regardless of quantity

Expense pricing mode is set per expense line and is independent of the section’s display mode.

Pricing Occurrences

When a module appears more than once on different elements, Darwin prices each occurrence separately. The underlying pricing data is stored and balanced per occurrence — the grain at which quantities and rates are resolved — before rows are grouped for presentation. This is the load-bearing invariant behind section grouping, cost breakdowns, and the disclosed schedule in client proposals: changing how rows are grouped can never move a cent of any figure.

Section Lifecycle

Operation	Description
Create	New section with name, optional client label, margin values
Patch margins	Update margins for one or more cost types on a section
Reassign	Move all lines from one section to another
Delete	Remove a section; lines must be reassigned first

Sections can be marked Ready to stamp audit context — the audit records who marked it ready and when, and moving away from Ready clears the stamp. Margin changes are audited with their previous and new values. Section status changes are locked once the estimation is approved.

Workflow Role

An estimate is created with a default section
The estimator organizes work into sections reflecting trade categories, project phases, or work packages
Different margins are applied per section based on commercial strategy, risk profile, or client agreements
During review, section margins can be challenged and adjusted
Upon approval, sections and their margins are locked as part of the baseline