I have a similar issue, wondering if you can help: A new(er) GIS map doc, the data frame coordinate system and all data was captured (GPS) and drawn in NAD_1983_UTM_Zone_15N (matching the ESRI World Imagery). All datasets, aerials, parcels, street centerlines, etc. match, no issues there.
UTM Zone 15N is in meters, I am displaying my units in feet. What I'm not understanding is that, for instance, I have a sewer main that measures (in reality and in my GIS) at ~533'; it displays (in the main's SHAPE_length field) as only 165. I can do the math, knowing that this is given to me in meters, approx. 1/3 of the actual distance.
No matter what I do, I cannot get the map to display and measure everything in feet, representing the reality of field measurements. I've set all my datasets, aerials, parcels, and map document into my preferred coordinate system (NAD_1983 StatePlane Kansas South FIPS 1502) (which is in US Feet), then everything gets even more screwy - a mile section only measures about 1600 map units...