How does the score system work? 

These settings determine the score provided for each match. 

• An import record that had 2 AVLs (one already loaded) and an existing customer part number would get a score of 25 and the new AVL would be set to be added on completion. 
• Another part that matched by MANEX number and description (exact match) would score 70. 
• Another part that had both AVLs but no other matches would also score 20.

The record with the highest score would be selected by default (or the one matched first if two records had the same highest score) and the system would alert the user to other possible matches.

What does match REV sort and overage calculation do? Rev sort (ascending/descending) indicates how to sort multiple records of the same part number. It will pick the first matching record. In other words, other things being equal, do you want it to select the latest revision (descending) or the first revision (ascending).

How does the Skip empty REV field work

In the BOM settings menu user has option to Skip empty Rev field.  Skipping empty Rev fields means that an empty Rev isn't treated as a rev. It can match any rev. If you don't check the option, then an Rev is empty( or non-rev) it will only match to an existing part without a rev.