Unless you own the parcel of land on which the franchise is going to exist, you will need to figure rent into the franchise costs. (commercialcapitaltraining.com)
While you aren't wrong in your initial population density idea, this more has to do with the value of land in densely populated areas than actual density itself. (politics.stackexchange.com)
I kinda fall on the side of throwing numbers at it in an effort to raise the odds of landing on more good picks. (sbnation.com)