This is a tough question to answer, because there are so many possible scenarios, but I'll try to give you an idea of what I understand. Let's say a bettor is putting $10 on every game for an entire season. Let's also assume that the odds of the games bet on are either +200 or -200, so either a fairly heavy favorite or fairly heavy underdog. In a 100 game season, let's also assume you bet evenly on dogs and favorites. Now, let's say you go 40-10 on favorites, for a profit of $100 (40 wins of 5$ and 10 losses of 10$). For the underdogs, you go 10-40, for a loss of $200. You are down $100 on the season.
Now, realize that at -200 odds, you are supposed to win two times for every time you lose, and at +200 odds, you are supposed to win once for every two losses. Therefore, this split (if there is no skill/luck involved) would result in about a 33-17 record on favorites and a 17-33 record on dogs, and the bettor would end up breaking even on the season. However, in the scenario I presented, the bettor was able to win 7 more games on favorites than he statistically should have, but he lost 7 more games on underdogs. Even though his luck pretty much evened out, he is down $100 on the season, because he valued dogs more, and he did not have a good season betting dogs.
In other words, betting 10 a game regardless of the odds washes out your record for favorites, and makes your dog plays more meaningful to your final bankroll. To adjust, the bettor should we wagering MORE money per bet on ML favorites and LESS money per bet on ML underdogs so as not to overvalue the dogs.
"Flat Betting" will value your bets on dogs and favorites equally in the long run. As opposed to the way most people bet (bet exactly 1 unit on each game), flat betting makes your record betting on favorites more prominent in your bankroll, and betting on dogs less prominent in your bankroll, AS IT SHOULD BE, since underdogs are less likely to hit.
If you are especially good at betting specifically favorites or dogs, then "flat betting" is probably not for you, but for most systems and bettors, "flat betting" is the best way to keep a bankroll that corresponds to your betting record.
that's exactly what i'm looking for. Thank you lawstyle, and thank you Vanzack for everything in this thread