I say, and with God's success: It is not a condition for the passage of a year to apply to all wealth, but only to the nisab. If one possesses a nisab at the beginning of the zakat year and then at the end of the year possesses multiples of the nisab, for example, he must pay zakat on all the wealth he has that is subject to zakat. As mentioned in the ردّ المحتار (2: 8) and البحر الرائق (2: 222). And God knows best.