add ability to modify "ratio" during inventory reception

We are currently experiencing a high volume of errors in our ratios on products during the PO receiving process.  In testing 4x this morning, we noted that if we catch the error before we send the PO (and fix it on the product screen), the ratios correct themselves in the PO, but if we find them after we've submitted, we don't find a way to correct the ratio.  We'd like the ability to fix the ratio during the receiving process (either by letting the changes on the product screen port over if the product has not been received or by giving the ability to modify the information that is tagged in the PO itself, or other if you have a more eloquent solution).

We're working on putting in place the correct behavior to validate ratios before sending the PO, but for-see the need to correct remaining.  It's an easy detail to miss given the quantity of items ordered any given day.

What we note is that if we notice an error in the ratio BEFORE we “send" the PO, we can go to the product screen, correct the ratio, and it is reflected correctly in the PO that was pending send.  If we note an error after it is “sent”, we can change the ratio on the product screen, but it does not correct on the PO that was sent and is now pending reception.  From behavior, it looks like those ratios get trapped in the PO details once submitted.  We’re looking for a way to correct that information before we receive because the error throws off the total value by a lot.

In our test, the ratios that seem to drive this are those related to the Vendor.  

See below for updated ticket specs