Well, there isn't any official information available on the admission process to JBIMS through CMAT only from next year.
As of now admissions to JBIMS is through CET...CET has its own process of GD/PI and in that all the aspirants who have applied for the exam are called. After the GD/ PI results are out a consolidated score of your written score as well as GD/ PI score are considered and then they see whether I am eligible for JBIMS or not.
This year they have allowed admission through CMAT only through all India quota but from next year CET would be scrapped and they would be considering only CMAT scores. Given the reservation of seats so far and there are chances that the Maharashtra quota would remain for admissions to JBIMS.