CCA Calculation is different in T776 and TP-128

I own a rental property with my partner, split 50%.

 

We have made some additions to the property this year and have added the value as CCA in T776's Area A with the Easy Steps method.

 

In that field, we have put the full amount, let's say 5000, in both our forms.  However, when we switch to each of our Quebec TP-128, the amount entered in 2500.  We cannot change that value without overriding it.

 

Why is the TP-128 value different here?  I expect the same amount as the federal at 5000.