@VintageFamiliar What @diophan said.
The way we have our spreadsheets written is that they deal exclusively in wins - The number of match wins Shops has against Gush is the number of match losses Gush has against Shops and so counting losses is somewhat redundant. Doing this, I guess Draws would count as losses for both parties, but the net result is that the match isn't counted as no winner was determined.
If you were to count wins and losses separately and include draws as losses you would depress the overall win percentage of the field (using our method, the number of wins is always equal to the number of losses so the overall win % will be 50% - counting draws as losses means there will be more losses than wins and the overall win percentage will be less as a result). This will also disproportionately affect certain archetypes as Ryan mentioned. There isn't one correct way to do statistical analysis, though. Just whatever you do, I would mention it.