BMW CPO guidelines say that it should be replaced with OEM.
only if the car had its windshield replaced before it was grounded (taken as trade or lease return) by the dealer is non OEM acceptable. non OEM used to be not acceptable period.
in your case, it should be replaced with OEM as its being done as part of the CPO process. i would politely insist, if that fails start going up the food chain and complain to bmwna.
what kind of glass shop are they using? hell, safelite can do the calibration, all it is is setting the kafas system to calibrate and driving. there's no targeting or any expertise needed, the system just needs to be put into calibrate mode and then drive it around.