Why are the SDA still obliged to bring tithes/firstfruits?

According to an Seventh Day Adventist chart (Redemption Series) six out of the seven festivals of Israel came to reality with the coming of Christ 1)Passover-Reality-Jesus became the Passover lamb(1 Corinthians 5:7) 2)Feast of unleavened bread-Reality-buried in the grave 3)Feast of First fruits of wheat harvest-Reality-Christ resurrected and became first fruits(1 Corinthians 15:20) 4))Feast of weeks-Reality-inauguration of the heavenly sanctuary and outpouring of the Holy Spirit(Acts 2:1-5) 5)Feast of trumpets-Reality-Advent movement-(The Protestant episcopal church) 6)Day of atonement-Reality-searching our hearts in repentance and confession(Joel 2:15-20) All these festivals are said to have seen their reality with the coming of Christ except the feast of tabernacles which is still in the future. I'm angling at the feast of first fruits of wheat harvest which i regard as (tithes/first fruits) which according to SDA also realized its reality(fulfillment) in the resurrection of Christ(1 Corinthians 15:20) In that regard why should the SDA still be obliged to bring tithes/first fruits?