# Calculating Chiller COP when Cycling

I'm calculating hourly COPs for a low-load air-cooled chiller. From what I understand (due to this post) there are two ways to do this:

COP Calc #1: $ COP,hr = Assigned Load / Power$

COp Calc #2: $ COP,hr = PLR / Corrected EIR$

The issue I am having is that when the chiller is operating for a fraction of the hour (meaning the load is lower than the minimum part load of the chiller), these calculations diverge and do not equal each other. When the fraction of the hour the chiller operates is 1, the calculations are equal, as in the last two rows. In the table below, I've used the equations above to do the calculations in the "COP Calc" columns on the right.

Why do these numbers diverge? Is it due to eQuest accounting for zeros in its average across the hour?