ACL reconstruction recovery: continuous cold therapy or ice?

I'm 4 days post ACL reconstruction surgery. I used a Continuous Cold Therapy System (Ossur Cold Rush) for the first 3 days...including at night. Then I had my first post-surgery PT appointment.  There, the therapist said that it is important for the muscles to contract back and forth, through the ice-on and ice-off pattern. 

I had read through various studies that I found online, that continuous cold therapy, where the temperature is "very cold water" versus ice, is better than a 15 minute/hour ice pack.   This is because the nerve endings are not damaged as they are through ice application.

Anyway, my PT is telling me to stop using my new $150 system, and to go to doing the ice pack regimen.   Anyone have any experience or input about this??  Thank you!