It depends on what you’re talking about so you should check the official competitor document but here is a quick summary for 2020.
Freestyle and DWAS = one level only.

Again in 2020, your Freestyle and DWAS levels will be the same and, as per the competitor rules, will determined by your length of time dancing (for lower levels), or your highest achievement in either category (for higher levels).
Other scenarios:
Those in Over 45s Freestyle will enter DWAS at the appropriate level as per the competitor rules document.
If dancers are competing up one freestyle level (as per the rules), they should still compete at the appropriate DWAS level.