Tax Deduction on Maintenance for Co-ops.

Ok, I get the fact that different maintenances have varying levels of deduction percentages. I also get that the percentage typically has to do with the underlying mortgage on the building as a whole. But the big question is...do you truly realize the Net maintenance that the brokers love to promote on those mortgage sheets they hand out at open houses? And how do you actually see the reduction? Is it realized on your own personal income tax return? If so, then wouldn't the realization of any deduction also be a result of your own personal tax return? It just sounds too simple when you see a listing stating something like "54% deduction".