https://www.uscis.gov/visabulletininfo

However, if a particular immigrant visa category is “current” on the Final Action Dates chart or the cutoff date on the Final Action Dates chart is later than the date on the Dates for Filing chart, applicants in that immigrant visa category may file using the Final Action Dates chart during that month.

Bn님의 말이 맞습니다. USCIS에 나와있는대로 final action date이 current이므로 3월달 역시 동시접수가 가능합니다.