No, the efforts are equal. A -2 is a -2.
But say you have two horses coming off negative 2\'s. Now they race each other. Horse A is in at 115, Horse B is in at 120. Horse A can run a negative 1 and finish even with Horse B even if it runs a negative 2. The fact that Horse B carried more weight and finished even with horse A means that that horse ran a stronger race, so they earn a higher figure.
Same thing would apply to ground loss. Lets say the same two horses at the above weights run against each other. Horse A gets a 1w 1w trip, carries less weight and beats Horse B by a length. But horse B carried more weight and got a 4w, 5w trip. So in this case Horse B will get the best figure, but Horse A wins the race.
The figures are calculated and they are what they are. But when we look at figures we are trying to figure out how the horses are going to run today, not what they did in their last race. So when two horses come back to race against each other at a later day, but this time at different weights, you may want to factor that into your handicapping on some level.
As this relates to the Preakness, the filly is getting weight from the rest of the field. Which means she has more room to bounce. She already has the best fig with room to spare, but she could run even slower and still win.
We are trying pick winners, not pick the horse that will run the best figure. Having a horse run the best figure but lose is not much consolation when you are tearing up your mutual tickets.