the shelf life is defined at general material level and not at plant level, the fields MHDRZ and MHDRB are stored in MARA.
A batch 123 can only have a different VFDAT shelf life expiration date in your plants if your batch level is plant level.
In short it is not possible in your case, as I know from your description that your batch level cannot be plant level.
The only solution would be to create an extra batch number and move the stock over to the new batch.
if you produce a batch of medicine and ship it to various plants in the world for distribution, then it is for me not logical that the same batch could for example have a different shelf life in Africa than in Europe.
I would be interested to know why the same batch could have different shelf lifes, can you share a real life example?