suppose an asset cost $12,000,000 on 1st Jan 2013, than on 31st Dec 2014 revalued amount 14m than on 31st Dec 2015 8m ..so if the FV of asset increases on next revaluation say 15m so asset amount should increase upto 8m or the cost amount 12m
The asset’s value is always updated to reflect the fair value on revaluation date. It doesn’t matter what was the initial cost or the current carrying value. So in your example, the asset’s new value will be $15m.