1111
Enter the contract, the price variation components, the bills (RA / final, each with its period) and the monthly indices - the escalation is worked out as you type.
Running account bills and final bill
One row per bill, in order. Each bill has its own period (start and end date); periods must follow one another without overlapping, and the final account bill must be the last. Values are the work done during the bill period at agreement rates; items not eligible for escalation are deducted.
Contract
Price variation formula
Escalation for component k = V × wk / 100 × (Ik − Ik,0) / Ik,0
V = value of work done in the bill period less items not eligible; w = weightage (%) from the contract; I0 = index of the base month; I = index for the bill period. The fixed portion plus the weightages must add up to 100 %.
Vk = 0.75 × Pk / 100 × (Ik1 − Ik0) / Ik0 × R (RPWA 100 clause 45)
R = value of the work done during the quarter, excluding materials supplied by the department, extra items at market / agreed rates and other items named in the clause; P = percentage of the component as approved in the sanctioned estimate (the percentages add up to 100 %); I0 = average index of the quarter in which the tenders were opened / negotiated; I1 = average index of the quarter under consideration. Labour: CPI-IW for the area; material: WPI all commodities; bitumen, HSD, cement, steel: their WPI.
Index series: type to search the index database (CPI-IW centres, every WPI item, and your custom indices). Typing a new name adds an index for this work only, filled in the Indices tab; to reuse one in other works, create it as a custom index in the database.
Monthly indices
Rows appear for the base month and the months of the bills. Grey figures come from the index database - CPI-IW (Labour Bureau, base 2016 = 100) and WPI (Office of the Economic Adviser, base 2022-23 or 2011-12 = 100, as chosen in the Contract tab) - and are used as they are. Type a figure to override one, or to fill a month not yet in the database; you can paste a block copied from Excel into any cell. To use a different index item for a component, pick it in the Formula & components tab.