The 90 Day Report ie TM47 report is for people staying 90 days consecutively in Thailand on many visa types. Not just DTV. For example B and O visa holders do it too. It seems many DTV holders are not aware of this as not told when visa issued by the MFA
If you leave and come back the 90 days resets. You would then only need to do the 90 days after 90 days consecutively in country - proviso 2 weeks before or 1 week after.