.* I would also look far and wide to adjacent neighborhoods to find any recent duplex sales and then assess and apply appropriate location adjustments.

For me its was double-wide mobile homes on their own land. 

@Bob Willis There is definitley a wide range for what people charge for their services and also depends on what they are exactly doing. 

Many times the info is entered incorrectly or incompletely into the MLS so it can be beneficial to keep the parameters wide. 

Norfolk is a diverse market and neighborhoods vary widely. 

And just like any good restaurant, you're going to do the work up front, to promulgate a menu that makes it easy for the customer to shop between options, all of which look excellent (don't put stupid overpriced low quality things on your menu), without having any menu items that don't also work for you as the restaurant. 30 year term at this rate, 25 at that one, maybe some with higher upfront fees and others with lower, and so on, we have a wide variety of excellent wines, you could also present that entire menu, but advise on which 2 or 3 might be the most appealing to go with their steak (we took something confusing, and did the work to make it easy).

I find that as an apartment wholesaler,  I can reach out to a larger group of people nation wide than attending local meetups and REIA groups.  

The walls we're covered in shag carpet for insulation and it was full to the brim with belongings on the day of closing.

Is it between 10-25%, or could be as wide a 15-45%, or typically hovers around 30-35%, etc?

I don't know if this helps but I am developing a plot of land in Zebulon North Carolina. it's an acre and I'm putting a double wide on it.