What’s the easiest way to determine floor number?

In designing a mid rise mix resi/commercial building, how to determine what’s the most efficient number of floors? Based on the following computations:

  • Total Gross Floor Area
  • Floor-Lot Area Ratio
  • Site Occupancy Percentage
  • Budget ng client

Say we have a vacant lot (500 - 1000 sqm), and client wants to build 7 storey just because, how do we justify na 5 storey lang pwede or pwede pa until 8th floor. How do we present this in a manner of computation?