I had a look through a late game save file with Duplicity and found that the game logs every use of at least the research station. In this particular game there where almost 5000 timestamped entries for this one station (I had dirt shortages so lots of small limited research jobs). I have not checked other stations such as metal refineries etc, but removing this logging may help reduce the huge save lags and memory requirements in later game cycles.
Ok I checked the save game file and I've gone down from 40 MB to 9 MB, so the mod is definitely working. But I just don't understand why my summaries would still be here, same with uptime statistics...
EDIT: now they're gone too. Is there any way the mod could shorten the X axis of the summaries according to how many cycles are recorded, so I'm not seeing a 900 long axis and 20 cycles long report?