My area it is $6 sf for moderate lvp. 3000 sf*$6 sf=$18000/10 year life span/12 months in a year= $150 for 1 item in a capex budget. 

You also also have cast iron sewer lines which are past their expected life-span.

My arm span is very close to six feet.

Another option is doing master lease options for that 2-3 year span.

However, comps gets tricky when your search spans over major roads, highways etc. 

. $6000/10 year life span/12 months in a year= $50 per month for 1 item.

  $6 sf * 1000sf= $6000/ 10 year life span/12 months in a year= $50 per month for 1 item.

Over the 10 year span from 2010 to 2020, the median price for a single-family home in Austin increased on average of around 8% year over year.You're correct that there's more upward pressure over time on prices for homes below the market median compared to those priced at or above the median.

Then ask what it's worth for them.There's no time for them to accrue any meaningful amount in that time span if charging purely interest. 

These aren't uncommon in project contracts that take a longer time...I know homeowner's like a 'fixed price', and it works on a remodel that spans a couple months, but in development type projects the schedule is too long to lock things in.