The difference is the LiFePO4 stays in bulk charge at the full charge rate (be it 0.4C or 2C) up until it is almost fully charged. LiFePO4 only takes 15 min to an hour in 'absorb' to reach 100%. Lead acid requires several hours in the absorb phase to get the last 10 - 20% of charge into the battery.
It is also important to get lead acid back to 100% as often as possible, so waiting those hours for the absorb to finish is important. LiFePO4 doesn't care about being charged back to 100%, so if you are OK with just going back to say 95% SOC, then you don't need the absorb phase at all.
On a related note - folks often claim that the care and feeding of lithium is more complicated than lead acid. This illustrates that this is not the case, lead acid requires a 3 (or 4 stage) charge profile, whereas lithium is fine with 1 stage, and ideal with 2 stage.
