The much-awaited pact on the $7.4 billion Iran-Pakistan-India (IPI) gas pipeline is likely to be delayed by at least a couple of months as New Delhi and Islamabad have opposed seller Tehran's last minute changes in agreement on pricing.The trilateral official level talks, which were supposed to be the last before the signing of the pipeline pact, hit a roadblock as Iran continued to insist on insertion of a clause for revision in the agreed pricing formula every three years.