I set out to test whether the claim that objectives upgrade faster on DBL is true. My hypothesis was that objectives upgraded faster the further south (and, therefore, the more vulnerable) they were. There’s some truth to that, but it is certainly not a rule.
The most surprising find is that the northern towers on ABL take 11 and 12 hours to upgrade fully. This is because they are served by only 1 Yak each and it continues to the Middle Keep after them which adds even more time. The next longest upgrade time is under 5 hours. I suspect that serving the north towers with 2 Yaks was one of the objectives when making DBL.
Conversely, the side keeps on ABL are served by 3 Yaks while DBL side keeps only get 2. As a result, ABL side keeps upgrade faster. ABL southern towers are also closer to their side camps and consequently upgrade a little faster despite being further from south camp.
DBL north towers upgrade much more quickly, though they have the longest cycles of anything on the map. DBL Middle Keep upgrades slightly faster as well.
With the exception of the northern towers (which are absurdly slow on ABL), there isn’t a significant difference in upgrade times and neither map can be said to be faster than the other.
It is worth noting that shorter upgrade times correlate directly to higher PPY values as more Yaks are reaching the destination per tick. These values are dwarfed by other values in the new scoring system, though.