The monthly rental rate is higher than four weekly rates because the rental company is billing for four full service visits plus the monthly rental fee, not offering a discount. You are paying for the unit and the service separately.
Your invoice breaks out a monthly rental rate for the physical toilet and a delivery fee to get it there. Then, it adds charges for each service visit, which is the weekly pumping and cleaning. A monthly contract typically includes four of these services. When you add the monthly rental fee to four weekly service fees, the total is more than if you just multiplied the weekly all-inclusive rate by four. The weekly rate you saw likely bundles a prorated rental and one service into a single price.
Operators do this because a unit on a long-term rental still consumes driver time, fuel, and deodorizer every week. The rental fee covers the unit's depreciation and administrative cost, while the service fee covers the labor and disposal. There is often no volume discount on the service portion because each visit has a fixed cost for the company. Check your contract; some companies offer a slight discount on the monthly rental portion for longer terms, but the per-service cost remains the same.
