What comes first? Cap Ex before the NOI or after?

[Ayodeji Kuponiyi]

Hey BP Nation! I shared another deal I'm underwriting and came across the issue of Cap Ex with some BP members. I included the Cap in my 55% of the expenses and apparently I was wrong for this that. I was told the following:

Gross Income - Expenses = NOI

NOI - P&I - Capex Reserves = Net Cash Flow

The problem is how do I account for Cap Ex in percentage in my initial underwriting? I assumed I could just deduct anything the inspector/inspection reports bring up from the agreed purchase price, Am i off?