The idea is to retain part of your available funds to spread it over time, so that your loans are split in small chunks and you can benefit from an average rate.
For example, if you have 10 bitcoins available and your split window is of 48 hours : then your available amount will be of 2.5 bitcoins after 12 hours, 5 bitcoins after 24 hours and 7.5 after 36 hours.
This strategy doesn't take into account the runtime changes (like new funds added in the meantime). It is rather dedicated to an initial spreading, or a large return of your funds.
Warning: this strategy is especially useful for large balance.
There are 2 settings for this strategy: