This tends to happen with new apartment buildings for the first 2 years or so, and its an artifact of real estate finance. For finance purposes, the building is valued on the theoretical sum of its leases when its at full capacity. If you have a 100 unit building where each unit rents for exactly 2.5k/month, then your building is valued on a multiple of of the $250000/month it generates. That value is used as capital for the real estate company that owns the building to use to get a loan to build another apartment complex. Where this gets tricky is that the max cashflow a building can generate is decreased when you lower rents in leases for for finance and accounting purposes,but when you give someone 1/2/3 months free rent the "max theoretical monthly rent" remains the same as if you hadn't given them the free rent. Thus, while the 2 months free rent is an effective ~18% rent decrease for the tenant, it doesn't impact the ability for the development company to borrow, and thats why it is widely used.
This seems about right. Also, there is a time frame when a new complex after completion transitions from a short term builder/construction loan to a long term permanent loan. For that loan as mentioned above the building is valued at theoretical sum of it leases by the bank. Thus for that loan it is better to show high actual rents and extrapolate to secure a better loan value / term.
