virturmart_product_prices table keeps growing

[quigley595]

Hi folks.....
I am developing a site at the moment, and am loading and deleting batches of products as I go through the development...  these are all the same products...
Basically, I load up all the products, test, and then, say I want to do a bulk change.... I could leave all the products in the tables and make the changes, but the way I have been doing it is to delete all the products, make the changes in a spreadsheet, then upload all the products again.
Prior to uploading, I delete the products via the normal back end facility in vm config.... select all the products, then click to delete them.

I have noticed though, that although the virturmart_products table is cleared, the virturmart_product_prices table is NOT cleared, and keeps growing.

I have just noticed this one table, and have not checked any other tables for this sort of thing.
Is this an issue??  should I be doing this another way??
I have cleared and purged the joomla cache, not that that should have anything to do with it I would have thought, but I did it anyway.

I am using Joomla 2.5.8   and    VM 2.0.18A
rgds
Mike