Opinions vary on this, but my own view is that it is only worth creating extra equally-sized tempdb files if you are experiencing allocation contention. Some people prefer to add the extra files to avoid the problem before it materializes, but there can be unwanted side-effects, including slowing down sorts and hashing operations that use tempdb. Overall, my vote would be for you to leave things as they are, but to continue to monitor for allocation contention, just in case.