Does the hawl (Zakat year) cease if the price per gram of silver decreases after the money reached the nisab at the beginning of the hawl, to the extent that its nisab becomes more than the amount I possess?

If the wealth reaches the minimum threshold (nisab), zakat becomes obligatory after the completion of one full lunar year (hawl), unless it falls below the nisab during the year, in which case a new year (hawl) is to be started from the time the wealth reaches the nisab again.