Actually, you will only see one VBK file.
After the first full backup, it will be forever incremental. The amount of backups will be determined by the number of days in retention that you have chosen. If the full drops outside of that retention range, it will actually merge itself with the next incremental and then clean-up the obsolete VIB file. The complete procedure is described in the beta manual. But again, you don't create a new VBK file anymore after the first backup unless you decide to create an ad-hoc backup (which is standalone, outside of the chain) or the chain breaks for whatever reason
Hope it helps