ERPs on 472kHz

I am pretty confident of my "just less than 5mW ERP" on 472kHz (with the very short Marconi) and am a bit suspicious of the claimed ERPs of some stations,, which, judging by the reports exchanged, may be lower than some people think. I think a lot more stations are less than 500mW ERP than they think. Perhaps losses are much higher than they think?