Calculate eddy current density from magnetic vector potential

Hello everyone, I try to check the FEA theory by calculating the current density from magnetic vector potential.
I obtain the magnetic vector potential on each mesh node of the study region (copper, non-magnetic) at 2 time steps in a row and try to calculate the current density according equation [Finite Element Method for Electromagnetic-Stanley Humphries (page 216). However, the result I obtained using equation (11.45) is far from the FEA result from Flux. 
Does anyone have any idea about these results or how to fix them?
I also attached the data in an excel file which includes x,y-coordinates, and magnetic vector potential at two time steps of each mesh nodes.
Thank you so much for reading it.