Are CAM allocations adjusted when there is a vacancy?

[Jason Conroy]

Say there is a 4 unit property where each unit is the same size. 3 of the 4 units are occupied the entire year and the remaining unit is vacant the entire year. Total CAM charges are $100,000. Is the proper allocation of these costs $25,000 per unit since each unit makes up 25% of the gross leasable area and the owner is not able to recoup the 25% from the vacant unit? This is my guess but I recently saw a prior year allocation from a prior owner that essentially would have charged each of the occupied units $33,333 since they each benefited from 33.33% of the total amount spent on CAMs. Clearly, this owner was trying to recoup 100% of the amount spent but I believe any sophisticated tenant would not have agreed to pay more than their allocation of the GLA. I saw no language in the lease that says lessees had to cover unallocated expenses for vacant units. I believe vacancy costs are covered by ownership but perhaps this isn't common?