Because the degree of variation in the inputs will skew the data. 

If it’s a BRRRR or flip — I’d also:Estimate rehab costsDetermine ARVUse the 70% Rule (or my own variation) to decide max allowable offerStep 4: Go/No-Go Decision (5 mins)At this point, I ask:Do the numbers hit my criteria?

That being said, the only way to "Legalize" the basement unit would be to pursue a Zoning Variation; or if it happens to be located within one if the new ADU Pilot Areas, that could provide an opportunity as well.

@Eduardo CambilYou posted variations of this question multiple times.

Anyone who thinks the economic benefits of a choice like this for you outweigh the risks needs to think this through.A quadplex that grosses $2,500 a month and is free and clear ends up being some variation of four apartments that each go for $625/month.

To tie this back to your original post, this is why you see this problem semi-consistently with variation across time and geography.

There are many flavors/variations, from the seller financing 100% or any other combination used in conjunction with a regular mortgage, commercial loan, private money, etc.

I often see variations of this questions.

I understand this has a big variation depending on location, age/condition of property, type of neighborhood, etc... and there are ranges given in the help section but I have found that the range is so huge, it can make a deal look terrible or fantastic.I also understand that potentially a more accurate representation of this might not come until after the inspection report but from my rookie lens of looking at things, this level of detail only comes after a submission of an offer.Maybe some factors that helps to narrow down the feedback.

There can be significant variations year-to-year and exceptions to the pattern based on local market conditions, economic factors, interest rates, inventory levels, and other variablesI am just saying at the end of the day, the small data set of statistic modelling for real estate would be entirely change to AI even now and future as we don't even need to code anymore.