\(P_0\) = Contract Price at Date of Tender
\(P_n\) = Final Contract Price
\({BEE}_0\) = BEAMA Electrical Equipment index figure last published before the date of tender
\({BEE}_{avg|t:40\rightarrow80}\) = Average of BEAMA Electrical Equipment index last published at \(\frac{2}{5}\) point of the Contract Period and ending with the Index last published before the \(\frac{4}{5}\) point of the Contract Period.
\({BEL}_0\) = BEAMA Labour Cost index figure for Electrical Engineering published for the month in which the tender date falls.
\({BEL}_{avg|t:33\rightarrow100}\) = Average of the BEAMA Labour Cost index figures for Electrical Engineering published for the last \(\frac{2}{3}\) of the Contract Period
Data
- A - Contract Price, \(P_0\) = £100,000
- B - Date of Tender, \(T_0\) = 20 Jan 2016
- C - Date of Order, \(T_1\) = 01 Apr 2016
- D - Completion Date, \(T_2\) = 31 Mar 2019
Calculation
Contract Days
- E - Contract days between C and D, \( \Delta T = T_2 - T_1 = 1094 \)
Electrical Labour Indices (Jan 2010=100)
- F - Date at one-third of Contract Period, \( T_{33\%} = T_1+\frac{1}{3}\Delta T = T_1 + 365(days)\) = (31/Mar/2017)
- G - Completion date, \(T_{100\%} = T_2 = \) (31/Mar/2019)
- H - Average of indices published between F and G, \({BEL}_{avg|t:33\rightarrow100} = \) avg(issue\(_{571}\) to issue\(_{595}\)) = \(\frac{1}{595-571+1}\sum\limits_{n=571}^{595} I_n \) = 122.1
- I - Index published for the month in which the tender date falls B, \({BEL}_0\) = issue\(_{556}\) = \(I_{556}\) = 114.8
Electrical Material Indices (2010=100)
- J - Date at two-fifths of Contract Period, \( T_{40\%} = T_1+\frac{2}5\Delta T = T_1 + 438(days)\) = (12/Jun/2017)
- K - Date at four-fifths of Contract Period, \(T_{80\%} = T_1+\frac{4}{5}\Delta T = T_1 + 875(days)\) = (24/Aug/2018)
- L - Average of indices published between J and K, \( {BEE}_{avg|t:40\rightarrow80} = \) avg(issue\(_{573}\) to issue\(_{588}\)) = \(\frac{1}{588-573+1}\sum\limits_{n=573}^{588} I_n \) = 109.2
- M - Index last published before the date of tender B, \({BEE}_0\) = issue\(_{557}\) = \(I_{557}\) = 93.1
Final Contract Price
$$\begin{eqnarray*}
P_n &=& \frac{P_0}{100} \left(5 +47.5\times \frac{{BEL}_{avg|t:33\rightarrow100}}{{BEL}_0} + 47.5\times \frac{{BEE}_{avg|t:40\rightarrow80}}{{BEE}_0} \right)\\
&=& \frac{100,000}{100} \left[5+47.5\times \frac{122.1}{114.8}+47.5\times \frac{109.2}{93.1} \right] \\
&=& 111,231.81
\end{eqnarray*}$$
Price Adjustment
$$\begin{eqnarray*}
\Delta P &=& P_n - P_0 \\
&=& 111,231.81 - 100,000.00 \\
&=& 11,231.81
\end{eqnarray*}$$