As part of our Shield research module, we only query the BSR values of certain ASINs (products) from the respective Amazon main and sub-categories if they rank to at least 175 keywords, which we query regularly.
Here you will find a list of our currently queried keywords in the research module: Number of keywords in the research module.
Unless the respective Seller Central was linked to Shield via MWS interface, we query the BSR values of those ASINs (products) from the contained inventory 8 times a day, independent of the keyword number to which they rank.
Here you will find instructions on how to link your Seller Central with Shield: How can I link my Seller Central (Seller Account) with Shield?
Additional keywords: BSR, no BSR, BSR missing, no value, why, why, bestseller, rank, rank, Amazon BSR.