9Power to deviate
In the execution of any of the works, the Company may deviate from the lines or situations thereof shown on the substituted plan to the extent of the limits of deviation and may deviate vertically from the levels shown on the substituted sections—
(a)to such extent downwards as may be found necessary or convenient; and
(b)to any extent upwards not exceeding 3 metres in the case of Works Nos. 4, 4a, 4b, 5 and 5a and to such extent upwards in the case of Work No. 4c as may be found necessary or convenient.