PR generated from MRP run exceeded maximum lot size

Hi gurus,

Need some guidance on the scenario below :

MRP run for material A

MRP type : VB

Lot size: EX

Maximum Lot Size : 200

Material A is a component of material Z. From a previous planned order of material Z, the requirement quantity of material A is 5000.

Now, after the MRP run for material A was done, a PR was generated with quantity of 5000.

My question is why was the PR generated with the requirement quantity of 5000 and not only did not obey the maximum lot size but exceeded it as well?

Thanks.