Using Maine as an example: The state has four electoral votes, two at-large awarded to the statewide popular vote winner, one to the popular vote winner in each of its two congressional districts. In a world where two parties combine for nearly 100% of the total vote, it is mathematically impossible for a candidate of one party to win the state while losing both congressional districts. Put another way, the popular vote winner of the state would have to win a minimum of three of those four electoral votes. As a result, our prior approach only allowed for one electoral vote to be allocated differently than the state winner.
While the above is all still true, the trade-off was that users were unable to rate each district indivdually. This became an issue in 2016 and could very well be again in 2020. Now, for example, we can rate District 1 as safe Democrat and District 2 as likely Republican, with the at-large rating able to be something other than those two.
270toWin Electoral Map
Background on Maine/Nebraska Allocation Method