el-remmen
Moderator Emeritus
We need a context to evaluate this - can you group by between long rests? Deadly is assuming it's one of a series - if it's the only battle during a day it's far from that. Heck, even if it's just an early battle surrounded by easy ones. On the other hand, four deadly battles in a row is more meaningful.
Also, I do notice that the DMG calculations tends to put too much focus on multiple opponents, especially weak ones with a boss, that artificially shows harder than it is.
By looking back at session notes, I added some detail about rests.
For the first adventure: The party took a long rest after encounter 2 (right before going down to the dungeon level), encounter 4, and encounter 7 (though that last one was after the final battle and the 8 skels were a random encounter)
For the second one, they took a short rest between encounters 12 and 13 and a long rest after 13 (which is when they headed back to town)
Hope that helps.