The software does a great job in terms of timing.  Also, it deals very efficiently with QRM from adjacent stations.   What is unknown is how your radio AGC deals with strong signals.   What I find in a crowded band, when I'm transmitting, other stations I saw on my waterfall are receiving.   Also, the software will select if you should use even or odd  time segments.   Although I've called stations and had others answer by the station I was calling, I wait for them to send RR73 or RRR and then call them again.    There's lots of "channels" in the WSJT-X FT-8 segment.

I find that many stations are running excessive power.  Not wanting to start a power war but remember we should run the power needed for effective communication.  And this is not a specifically a "low power mode".    Just try working the JA's on 160 M and you'll see what I mean.   I typically run 100 watts or less, depending on band conditions, although I may run more if needed.  But never run everything at full bore just to make contacts.

73

Bob, K4TAX

Yes, I've had issues myself with FT-8 on 40 meters. I had a perfectly clear slot, was calling a DX station and suddenly I saw KB5VXX QRM...I immediately hit halt TX and went to look where I was transmitting, but still didn't see anyone in the slot I had chosen. Idk, but it was pretty crowded. First time I've ever been called out for QRM. I call myself trying to be careful. Oops. 

Virus-free. www.avg.com