Understood, it just irks me when I read people thinking it is the same oil. Amsoil loads additives in their oils for this case.
Each filter change equals 14% of the oil changed. So yeah, 7 filter changes is a full change of oil. The bigger factor is the filter change.
With a sump that large I would do the same, and have with heavy machinery taking gallons of oil. I would like to see the bottom of your oil pan.
On a funny yet alarming note, I have found bolt heads and other items on the bottom of a pan. All from assembly, but did cause pucker factor at first.