AQL VALUES IN SAMPLING SCHEMES

Hi QM Team,

We use AQL Value in Sampling schemes. AQL Value is nothing but Acceptable quality level. Along with this AQL value we also define sampling plan in sampling schemes. In sampling schemes we have to define C1 & D1 values.

Now C1 is nothing but :For an attributive inspection, the highest number of nonconforming units or the highest number of defects in a sample that leads to an acceptance of the inspection lot.

and D1 is nothing but : For an attributive inspection, the lowest number of nonconforming units and/or the lowest number of defects in a sample that results in a rejection.

So by defining C1 & D1 we are defining acceptable quality level .

So my question is WHY AQL VALUE IS REQUIRED ? OR IN THE OTHER WAY HOW AQL VALUE WORKS WHEN WE HAVE ALREADY DEFINED C1 & D1? WHICH TAKES PRECEDENCE C1&D1 OR AQL VALUE