Capacity is per room, not per building. Babies require far more staff than pre-schoolers, so a setting can be full in one room and half empty in another, and counting total places hides that entirely.
Ratios are an hourly obligation. Lunch cover, staggered shifts and a member of staff going home ill are what break them, so the rota has to be checked against attendance in real time rather than planned on paper.
Billing mixes two systems. Funded hours claimed from an authority and private hours charged to a parent land in the same invoice, and getting that wrong produces either an angry family or an unclaimed entitlement.
Some records cannot be approximate. Allergies, medication, who is authorised to collect a child and who has parental responsibility are details where an error is a serious incident rather than an inconvenience.