Assuming the 8000 packs are 5c, that's a 40a charge rate and not many chargers get that high.
The ones that do certainly know what a pack can take and won't give more than that. Probably why they don't even bother to list a max charge rate.
Most of the chargers over the last decade will not charge higher than the pack wants to take also so you can just about set it to max and let it go.
You may set it to 12a on an old cheap pack and a good charger may charge at 6.85a because it can sense that's all the pack wants to take.