A slight change from the original Spiff text from More Cosmic Encounter to the FFG version....

Old:

Whenever you are the offensive player in a challenge, both players play Attack Cards, and you lose by a total of 10 or more , you take one token you would otherwise lose to the warp and place it on the winning defensive planet.

New:

As the offense, when you lose an encounter, if both players played attack cards and your total was 10 or more less than the defense’s , you may use this power to land one of your ships that would otherwise be lost to the warp on the winning defensive planet. The ship coexists with the ships already there. This power does not allow you to coexist in places or with aliens that state otherwise.

What this does rules-wise is allow Anti-Matter and Loser a bit more power over the Spiff, because the Spiff can no longer crash-land on A-M's/Loser's planets by having a total that is 10 or more higher than the defense. Was this rewrite an intentional revision of the power, or just a wording change that accidentally resulted in the nature of the power being modified?

I would guess that it was intentional, considering how "10 or more less" is otherwise clunky. Doesn't make sense thematically though.

if the core mechanic of the Spiff is "enable wins by way of significant defeats", then using something like "margin of defeat" is a better term to use. Now Spiff is powerless to any alien that uses something other than "highest total wins" as a victory condition.