Yeah if your wheel has never shifted forwards or backwards when it was 10mm further into the dropouts. Why would it start shifting when it's just a little further back, it shouldn't be any different. I think someone suggested a half link in this thread which you could do, but if it were me I wouldn't even bother. I thought it may be dangerous when I had it that far back, then 3 months went by and the winter was over. And I didn't think about it until I was taking my winter tire and cog off.