CSC said the shares for The Trafford Centre will be issued at 400p rather than the 368p originally agreed.
The number of shares Peel will receive has been cut to 205.9m, from 224.1m as a result of the new deal.
Peel's holding in CSC will be cut to 23.2 per cent from the original 24.7 per cent that was on the table.
Peel chairman John Whittaker said: "The Trafford Centre is an outstanding retail and leisure destination in its own right. Its mix of retail, entertainment, theatre, leisure and sporting facilities has driven significant year-on-year growth in footfall which has led to substantial value out-performance.
This successful formula applied to CSC's portfolio will provide a unique platform for growth for the benefit of all CSC shareholders."