I say, and with God's help: In zakat, the passing of a year is considered, meaning that the wealth must reach the threshold amount equivalent to 100 grams of gold at the beginning of the year for the zakat to be valid, and at the end of the year, it must not fall below the threshold. If it was 1350 dinars at the beginning of the year, it is considered the threshold, and if it increases at the end of the year, then zakat is due on the entire amount, meaning on 6000 dinars, and God knows best.