What is the use of XXX1.SerialNum ?

Hi,

I just want to understand what is the utility of the XXX1.SerialNum field (like INV1.SerialNum)... it is not linked to the serial numbers we select for the document... !?  Why can't we see back in this cell the SN we have entered for an item with a quantity of 1 for example ?

I've tried to find information in the SDK / REFDB / HOW TO help files but there is no help about that...

Thanks,

Luce