Jaydholakia - Hello, you need not wait for 16 days between the in-center GMAT and the GMAT Online. The 16-day waiting period is applicable in each exam format. For instance, if you wish to take the GMAT in the test center, you need to wait for 16 days before your next appointment. Likewise, you need to wait for 16 days between
However, there is no such waiting between the in-center GMAT and the GMAT Online. In fact, you can take the two tests on the same day. I hope this information helps.