Each school has their own policies on accepting transfer credit and test-out credits. Some colleges have limits on the number of credits transferred in because they may feel the student should have a learning experience related to the mission, vision, and curriculum of that particular institution. Some colleges have a requirement called "Residency requirement" which is termed to ensure students take courses at that institution. Other colleges have no limit. You can research this through researching "transfer credit acceptance policies" or "IB acceptance policies" at the schools you are interested in attending.