Large dps decrease on FFlogs compared to ACT logs


New to ACT and FFlogs here. So I recently saw that the dps shown on FFlogs is much lower than what is shown in ACT. typically 200-400 dps lower. I have read that FFlogs handles a few things differently, such as overkill, dots, and start/end of encounters, but none of that should account for around 300 dps loss on every fight when I upload. Anyone has an idea about what could be going on?

EDIT: I can see aswell that the fights are listed as being much longer, typically an entire minute, on FFlogs compared to act. That would explain the DPS loss if the fight is “stretched out” an entire minute, but I wouldn’t know why FFlogs lists the fight as being that much longer.

Thanks in advance