This post answers what is Mars' gravity at its highest point (Olympus Mons) compared to the Earth's and Mars' standard, it's 0.3736 g (Mars standard is 0.3794 g). This also seems to be the lowest gravity anywhere on Mars. Mercury has a similar surface gravity to that of Mars, and I'm trying to figure out the gravity at Mercury's highest point (which also may be the lowest gravity anywhere on the planet).
Mercury's mass are 3.3011e+23 kg and Mercury's mean radius are 2439.7 km. This results in a surface gravity of 3.7014 m/s² or 0.3774 g. Mercury's highest elevation is 2.78 mi (4.48 km) above what is considered the sea level. So I add these 4.48 km to the mean radius which results in 2444.18 km, thus the gravity would be 3.688 m/s² or 0.3761 g. Since Mercury rotates extremely slowly, I guess any difference in latitudinal gravity is tiny enough so we can neglect it here as well as any equatorial bulge (the highest point is close to the equator). However, there may still be differences in mascons.
Did I make any mistake? Do we know whether any mascons are to be considered? If I'm right, Mars' lowest gravity is lower than Mercury's lowest one, despite Mars' average gravity being higher than that of Mercury.