Often when you purchase products and then unpack and shelve them you may not know which vendor they are from. In this case you can assign just one vendor to the count sheet location. You should choose the vendor whose products you received most recently so that the value of your inventory when you take a count will be accurate.
BUT in order to make sure your On Hand is accurate you will want to create a location for any additional vendors. You can call this ghost location anything you want. It's really just a place to keep the other products so you can zero everything out when you start a new count. Here is how to automatically zero out your on hand before taking a count.
Here's an example - you purchase Hunt's tomato sauce by the case, sometimes from Sysco but sometimes from GFS. Each time you get a new invoice we'll update the price of that ingredient. But when you unpack and stock the cans you don't know which cans came from Sysco and which from GFS. So when you count you are counting the total cans, and you now have an On Hand valued at the most recent price as long as the most current vendor is in a location that is counted.
Between the last count and this most recent count you may have received invoices from both Sysco and GFS. If you only have Sysco as the vendor in the location where you store the cans and then you zero out your counts you will still have an On Hand for the GFS cans from their last invoice.
In order to zero out the GFS cans you'll need to create a ghost location and add the GFS cans there. Then when you take the count and zero out all your inventory the GFS cans will be zeroed out and stay at zero for this count. That's fine because when you count the Sysco cans you will still have an accurate total of all the Hunt's tomato sauce cans.
If you then start purchasing this product from GFS you will want to put the GFS in the count location and move SYSCO to the ghost location. This is so the price of the product reflects the newest price AND we zero out any SYSCO received goods since you are now counting ALL your tomato sauce cans.