The biggest time increase comes in searching multi-years of data for resold houses and also collecting the data to analyze for trends. Making charts and graphs also adds time. Writing a narative to put the whole story together adds time.
I think that the poll is flawed. The lack of a definition of "average how much time do you have invested" is the problem. What is that to include? Just research and writing or including the inspection, including inspection of the comps and including travel time from the office and back to the office. There are days that it can take me 30 minutes to get to a specific neighborhood and other days that it can take over an hour to get to the same neighborhood.