updateBuildsList calls keepLastBuilds by default what end up with the following builds no consider by the plugin for all the option running in perform:

if (r.isBuilding()) continue;
if (r == lastBuild) continue;
if (r == lastCompletedBuild) continue;
if (r == lastFailedBuild) continue;
if (r == lastStableBuild) continue;
if (r == lastSuccessfulBuild) continue;
if (r == lastUnstableBuild) continue;
if (r == lastUnsuccessfulBuild) continue;
newList.add(r);
}

This might be an optional as is quite confusing as you can end up specifying you want `Max of builds to keep=X`, but then have in the build history X+DELTA.