Do you have a link where you can share this info? curious to know...

I'm not sure of a list of studied detergent levels in gasolines, but I agree that better gas is a good way to avoid the need for additives. Different retailers have different additives in them- below is the approved list of retailers from Top Tier, see http://www.toptiergas.com/
These are the retailers that have adequate levels of additives in all grades of gas per this consortium of auto manufacturers - a little gimmicky perhaps, but not many guides out there that I'm aware of

QuikTrip
Chevron
Texaco
MFA Oil Co.
Conoco
Phillips 66
76
Entec Stations
Shell
The Somerset Refinery, Inc.
Kwik Trip / Kwik Star
Aloha Petroleum
Tri-Par Oil Co.
Turkey Hill Minit Markets
Mileage Stations
Chevron Canada
Shell Canada
Petro-Canada
Sunoco Canada


I tend to stick to Shell and Chevron in my area...