5. The amount of grant payable at the discretion of and by the Scottish Ministers under regulation 3 towards the approved cost of an operation, other than the erection of a dwellinghouse–
(a)in a low level priority area, shall not exceed the lesser of 20% of the cost of the operation and £11,500;
(b)in a standard level priority area, shall not exceed the lesser of 30% of the cost of the operation and £17,000;
(c)in a high level priority area, shall not exceed the lesser of 40% of the cost of the operation and £22,000.