E.g. if you go to upgrade a science officer's "Tachyon Harmonic I" skill, and click the icon to get the "Skill Details" display, and look at the stats, then click the "^" arrow under the "Tachyon Harmonic I" box, the resulting "upgrade" stats //always// look worse.
E.g. for THI / 1, it said "50% chance: Knocks Back +5.6 feet, -25 Target Shields",
but for TH1 / 2 it said "50% chance: Knocks Back +5 feet, -23 Target Shields"
Since I figured this has to be a display bug, I upgraded. And now it says "50% chance: Knocks Back +5 feet, -25 Target Shields".
All the other stats similarly offered to generally get worse for me, but all now show the exact same values as THI/1.