You can also loot on 50/50 night, and have all presents looted up by the time 4:30 rolls around, giving you an hour in-game time to get off the surface (if you're on a mana it takes less then 0:20 to get off).
It is impossible to loot any presents during 90/10, the time the first presents land is around 5:05, and that gives you about 10 seconds to get off the surface. You can however go up on a 90/10 night if it is a day ending in a "6" because when it turns to midnight it switches to 10/90, and you have all the time in the world to loot up. So in summary, you get 7 days you can successfully loot all the presents, out of a 10 day cycle.
Also, there are more then 10 presents that drop on Abb, even during 50/50. There are close to 15 drops in a given night, of which 2-3 usually go out of bounds (everytime, same spots), and about 5-6 land on ledges. To get the ledged ones, you need to be skillful at mana jumping, be on a RD that climbs, have a tek jetpack, or keep climbing picks handy. This is annoying, but I've looted about 9-10 presents in a single night, solo, and it would be more but I literally can't make it to all the drops before they expire (have some downtime from killing Reapers/seekers/travel time).