Gigi, I need for you to check your model very carefully in order to ensure that I am using the best value for pump power leakage. Take time to verify that 4.0 watts gives you the best fit to the data match with Jed's excel file for the period after the drive pulses have ended.
If I recall you entered the coolant temperature as the initial condition for your model run. It will be better if you move far enough in time to a place where the water and the cell have the same temperature. Ideally, the heating will be mostly due to pump power input and little from the cell history within the desired region. I modified my simulation model now to use Jed's data directly for the input parameters. I adjusted my time increments to use the ones he measured to obtain a better match to what he sees. The results are quite interesting. Dave