Car seat test for preemie.... question

My friend's baby was born a few weeks early last Monday and has premature lungs. As of today they did a carseat test (a britax $300 seat) he failed the test and they are telling her to go get another car seat now for another test. They want to release him today!!!

I have a Chicco keyfit 30 to give her regardless but we feel like he is being pushed out of the hospital when he is not ready. He was born 8.3lbs and nurses well but his numbers on the monitor never hit 100, always 94 to under 100. Sorry I don't remember what those numbers mean.

Anyhow - have any of you had to get a different car seat to pass this test? I think that's insane. Her carseat is rated for 4-30lbs. Please some advice!

Oh and they told her not to use the snuza halo - I told her it's a great monitor and I would use it at home. doctors generally never recommend those things.