I think if it were me I would rather have full length feathers that have been split and ground than feathers that have been chopped, because everybody necessarily has their chopper set a little different than everybody else, so the chopped feathers are going to be a little different from the ones you chop yourself. When I make arrows, I consider the time it takes to chop to be insignificant, probably less than 5 minutes to chop enough feathers for a dozen arrows, and I can decide myself whether it is worth getting two chopped feathers out of one full length feather (usually it isn't, but probably your feathers are better quality than the full length feathers I buy).
I notice that 100 full length white feathers from 3 Rivers costs $76. Anyone who would be willing to split and grind your feathers for that price would be earning their pay, I think.