For a rental unit, why does turbotax automatically split the rental income and expenses by the partnership amount (50% in this case), but not the CCA calculations?

Turbo tax does not split CCA because there a cases where  depreciable assets belong and are used only by  one partner: example is a vehicle  ( each co owner has a vehicle with different cost and usage ) computer and so on. 

You need to calculate partners portion for each asset and enter it on appropriate tax return.

In my case, I don't need to use any CCA, but my partner/spouse does. When we use/expense CCA on his return it only reduces his total share by half. How do we record it so that he uses all of the CCA claim on his return.?