Obviously flying an LPC would be better, but what happens in the days before an LPC and in the Briefing? You think about the rules, procedures and drills, you read up about maneuvers and exercises you're likely to have, and get them fresh in your mind so that on the day you hit the ground running. At least that's what I do. And when I do that I tend to nail it when I'm asked to do something.
It's not a licence proficiency practice, it's a licence proficiency check, and the important thing is how you prepare for it. We don't suddenly go from being proficient to unproficient at the stroke of midnight, and for someone with a good amount of LPCs under their belt I would say a good briefing achieves 90% of the aim, certainly enough to award 6 months extra validity in such unusual circumstances.