What is business interruption (BI) cover and how is the indemnity period calculated?

Gross Profit: rate of Gross Profit multiplied by Reduction In Turnover, plus increase in cost of working (capped at Gross Profit rate applied to reduction avoided), less savings in costs; Gross Revenue: shortfall in Gross Revenue during Indemnity Period plus increase in cost of working (capped at reduction avoided); Gross Rentals: shortfall in Gross Rentals during Indemnity Period plus increase in cost of working; Additional Cost of Working also available as a standalone item

Item A: Loss of Gross Profit — sum produced by applying the Rate of Gross Profit to the reduction in Turnover during the Indemnity Period, plus increase in cost of working necessarily and reasonably incurred to avoid or diminish the reduction in Turnover, less savings; Item B: Loss of Gross Revenue — amount by which Gross Revenue falls short during the Indemnity Period plus increase in cost of working, less savings; Item C: Loss of Rental Income — amount by which Rental Income falls short during the Indemnity Period plus increase in cost of working, less savings; Item D: Wages (Dual Basis) — Rate of Wages applied to Shortage in Turnover during Indemnity Period plus increase in cost of working

Gross profit basis (Insured Profit defined as excess of combined Turnover plus closing Stock over combined opening Stock plus Uninsured Working Expenses); also covers Insured Revenue (money paid or payable for goods/services) and Insured Rentals and Management Fees; Shortage in Turnover is the trigger measure; Payroll cover also available; Standard Turnover is the 12-month pre-loss comparator period