I think it would depend on the charcoal being used. If you use briquettes you could hold a lower temp longer and cleaner, I say cleaner because in process of making lump or natural not all the would gets carbonized like in a briquette which means that lump may have particles not carbonized and would ignite and produce smoke as it burns.
Lump will also varies in BTUís per pound and varies in wood types per bag often lump bags contain a lot of useless carbon dust from the factory which means it will produce more dust that will fill in the gaps between the large pieces and decrease the air flow to larger pieces so temp will fluctuate more on a long burn. I use lump but always dump it out to get rid of the dust before I put it in my basket.
So after saying all that I really donít know