Removing the compounding info objects

Hi Experts,

I am having a problem with large master data tables in the production system. There are 2 custom info objects ZPCA_Doc and ZPCA_item for PCA document number & item number. ZPCA_DOC is compounded with doc_typ and ZPCA_Item is compounded with ZPCA_DOC info obejcts. The number of entries in the two info objects ZPCA_DOC and ZPCA_Item is growing everyday. The number of entries in the ZPCA_Item is nearing 20 million records. I think this is due to the compounding of the info objects. As this was developed few years back I am not sure why the compounding was done.

I need advice on:

Is it a good practice to compound the document number & document item info Objects?

Is it possible to remove the compounded info object on these info objects without deleting the infocube data?

Is there any other way to control the number of entries in these info objects?

Thanks in advance,

Shilpa