As a person who's judged a fair amount of contests, both skating and surfing, the scale is normally adjusted before every day and between divisions. For instance, on a 10 point scale, you don't want the winning kid of the youth division to be winning on a 4 or a 5. That's not as exciting for them, they want to tell their friends they got a 9. So, before each division, a head judge should be holding a discussion as some form of ground rules for ways the judges should be re-scaling their scoring (variety of tricks, use of obstacles, etc.).
Given those ground rules, as a judge, the first score of every event will set your scale. You hope for a pretty standard run that you can deem a 6-7, and then you have your base line by which you can judge every other run off of. The issue that can occur with this, is when the first skater of the day puts down an absolute banger of a first run, and then you're forced to make a decision as to how much better of a score you think is possible, and then score based off of that. A real example that comes to mind is from the Rip Curl Search surf event in Mexico, where Mick Fanning took off on the first wave of the day, and got what was clearly going to be the best wave of the day, however the judges scored it to give room for better rides, and gave him like a 9.8, and then there wasn't a perfect 10 awarded that day/event.
Of course, numbers are truly arbitrary, and I think that it is most important for the judge to get the "feel" of a contest right. Normally, I define this to other judges as being able to write a separate list without your scores of what you think the outcome should be, and your scores should reflect that list as closely as possible. That normally helps to avoid the murmurs of "X person got robbed".
All of this to say, yes, women's should probably have a different scale. To anyone worried about scoring in the future, as stated above, the top of the scale should be the best that they think is possible that day. While holding everyone to the same standard does seem equal, at the end of the day being scored higher makes everyone feel better.