I would expect that the contrast range in those abandoned farmhouse interiors would be well within the limits of normal exposure and normal development----so long as you are not interested in detail in any kind of outside areas, such as outside the windows or doors. If, as I surmise, you are underdeveloping in an attempt to hold detail in those outside areas, or areas very close to the windows and doors, of course the remaining tones are going to be "flat."