It turns out that Go! did change its formulas slightly- it just took a while.
They've been updated now in the database. I also left up the old version of the most popular one for ferrets (the chicken/trukey/duck one) for comparison. The new formula seems to like it has a higher variety
of meat (more meat ingredients listed), but an overall lower meat content (slightly lower protein and fat). The changes do not move it up or down any places on the ferret food chart though.
The old entry will be removed in a few months when they old formula is no longer in circulation.