How does vacancy cost sharing affect tenant bills?

When tenant bills are generated, the system uses the building's vacancy_cost_share_pct to calculate how much of the common area costs each tenant pays. Here is the step-by-step calculation:

Step 1 — Common area portion: The system calculates what percentage of the building is common area. For example, if total_area = 1,200 m² and rentable_area = 1,000 m², common area is 200 m² (16.7%).

Step 2 — Split the invoice: An incoming invoice (e.g., €10,000 for heating) is split into two parts:

• Common area portion: 16.7% × €10,000 = €1,670
• Direct (rentable) portion: €8,330

Step 3 — Calculate occupancy: The system sums the effective area of all active tenants and divides by rentable_area. If tenants occupy 800 m² of 1,000 m² rentable, occupancy is 80%.

Step 4 — Apply vacancy cost share: The common area portion is further split:

• Occupied share: 80% × €1,670 = €1,336 (tenants always pay this)
• Vacant share: 20% × €1,670 = €334

If vacancy_cost_share_pct = 0%: Tenants share €1,336. Owner absorbs €334.
If vacancy_cost_share_pct = 75%: Tenants share €1,336 + (75% × €334) = €1,586.50. Owner absorbs €83.50.
If vacancy_cost_share_pct = 100%: Tenants share the full €1,670. Owner absorbs nothing.

Step 5 — Distribute among tenants: The common area amount allocated to tenants is distributed based on the cost allocation matrix (or area-based fallback). The direct portion is always distributed proportionally to each tenant's effective area.

Where to verify: After generating bills in Tenant Billing, each line item shows its allocation basis. Look for "common_area_amount" and "owner_share" in the allocation details.