The extra multi doesn't show up until you get your first XP/Gold tick the next round.
If your team loses, you'd normally go to x1 on the next round. The very next time you get xp/gold, your multiplier will then go to x2 (and your xp/gold for that tick will reflect that).
If your team won the previous round and you got valor, you'll be x1 more than you start the round with, on the very first tick you get.
Also, what no rules said is accurate for how you get valor, as long as you have more than double the average score for your team, during that round (I've heard others say it's as long as you have double score or higher than the average of both teams, but that doesn't make sense to me).