“The employer shall not interfere with or prevent the principal agent or any agent from exercising fair and reasonable judgement… etc

This clause prevents the employer instructing the principal agent to only certify ‘x’ in a payment certificate when the contractor is due ‘x’+’y’ …

The contractor may terminate the agreement forthwith under such circumstances

See: 6.1P-29.14.3; 5.0P-5.6 & 38.1.3