There is a possibility that battle submitted client has different result when compared to your machine. For example less available memory or different java version. So if your algorithm is CPU intensive it might be forced into the "skip turn" regime and then score will be very low.
For the last year my machines were major battle submitters and I use to run them with old Java, so if yours was compiled with newer Java it would automatically lose, since it would not be able to fight.
I do not think that it is robocode version issue, but I recall that there we some glitches with reporting when we moved from 1.8 to 1.9. I think the only fix in 1.9.1 to 1.9.2 was in the score submission.