A lot of distilleries do the same with mashbills... It has to do with where/which rackhouse they are stored or located, which level rick in the rackhouse they are stored, as well as the mashbill.
For instance, Jim Beam only has two mashbills. Jim Beam & Old Grand Dad. Where the JB mashbill is stored & how long it’s stored designates which brand. JB mashbill makes Beam, Knob Creek, Baker’s, & Booker’s. Old Grand Dad mashbill makes OGD, OGD Bonded, OGD 114, get this...Basil Hayden. Yes, Basil Hayden is just older OGD stocks proofed down to 80 proof & stuck in a fancier bottle.
Also, Stagg Jr is just higher proofed Buffalo Trace. George T Stagg Antique Collection is just Buffalo Trace honey barrels aged longer. Eagle Rare is the same mash as both just aged lower in the rackhouse for at least 10 years.
I could go on & on... I still like Weller & Blanton’s though.