[EDIT 5/7/2012: Patch 1.2.2 corrected this error. See the analysis here.]
Yup, it is time for another slicing post.
It looks like 1.2 had a few undocumented (maybe even unintended) changes to slicing. Over on the forums, a few posters have been noticing some pretty dramatic losses and changes to the grade 5 and 6 missions - particularly the rich missions.
So I returned to my army of slicing alts, and collected data on 400 Grade 5 and 6 slicing lockbox missions with companions at 10k affection, and then compared those results to the data I'd collected before.
These curious results come from the double-RNG nature of slicing returns.
Each lockbox has two attributes that determine its average yield: its level and color. Grade 5 missions can return level 42, 44, 46, and 48 lockboxes. Grade 6 missions always return level 50 lockboxes.
Before 1.2, green lockboxes returned an average of 160% of the credits of their white counterparts. Since 1.2, green lockboxes are worth less than white ones - earning 80% of a white box on average.
*Moderate missions return White lockboxes.
*Abundant missions return Green lockboxes on crits, and White otherwise.
*Rich missions return Blue lockboxes on crits, and Green otherwise.
This helps make sense of the original results. Because White lockboxes were unchanged, Moderate missions were unchanged. Abundant missions were only slightly affected because they only return green lockboxes on crits (15-20% of the time). Meanwhile, Rich missions return green lockboxes on noncrits - now a generally a 1000 credit loss compared to the cost of the mission. They only remain profitable because blue boxes (average 6250 credit return) can offset those losses on a crit.
Overall: all slicing lockbox missions remain profitable in 1.2 (I'd definitely make and sell augments instead... but more on that later). Moderate and abundant missions now have higher earnings than rich-yield missions.
I do find it odd that they'd choose to deliberately target green lockboxes to nerf. Without understanding the reasoning, it feels more like a bug than an intentional change.
[EDIT: caught math error and updated returns for green 42-48 lockboxes.]