Missing pc model for some pcs

In working with pc counts and identifying by model, I found the PC count to be higher than when  joing two views to get pc name and model;

vComputer and vHWComputerSystem.  There are 62 pcs that have null as model.  The majority of our pcs/laptops are Dell  models and those names ARE in  vHWComputerSystem so it is not a question of not identifying the model name. Also it is not an entire model  'line' that is missing.  If inventory can identify, for example, Optiplex 7050 for most pcs, why not ALL?

How do I fix this?  I ran a delete inventory and run a new inventory on the 62 pcs, but those that finished the inventory are still missing the model.

BTW, I use TOAD for SQL against the database- views and results .jpg attached