translate English to French: There is no explanation of why Lavcevic has used the original rather than the revised contract sum.  First, Lavcevic has calculated the quantum by deducting the value of the work allegedly completed (USD 115,797,560) from a contract sum of USD 183,572,549.
Tout d'abord, Lavcevic a calculé le quantum en déduisant la valeur des travaux prétendument achevés (USD 115 797 560) d'une somme prévue au contrat de USD 183 572 549.