Draft Ring

Bear with us while we illustrate.
The 100 most popular drugs probably represent somewhere between 3.3% and 5% of the drugs in your formulary (that require pill counting).  These same 100 drugs probably account for about 33% of the scripts filled by your pharmacy.  Many pharmacies install automation to help alleviate the burden caused by these scripts, and, hopefully, save money at the same time. 
When doing the cost justification, it rapidly becomes apparent why the most popular drugs are chosen.  The time savings on a per script basis is small, even when the comparison is between manual counting and various types of automated or semi-automated counting.  If the capital investment required for automation is large then the number of scripts filled per day must be correspondingly large.