Following my Khubulov chemistry testing yesterday:

I've been running a test this morning continuing with Khubulov, testing other individual chemistry levels and seeing at what number he can no longer do the step over.

TLDR: At 8 chem (2 dribbling chevrons, 2 shooting chevrons) he can still do the step over. At 7 chemistry (2 dribbling chevrons, 1 shooting chevron) he cannot do the step over.

Conclusion: Either the dribbling chevron does not conclusively indicate a fixed increase in stats, or something else is going on.

Full results with positions and other details:

10 chem, 100 team chem, 4231(2), No loyalty bonus, RM card at RM position = yes
9 chem, 100 team chem, 4231(2), No loyalty bonus, RM card at RM position = yes
8 chem, 100 team chem, 4231(2), No loyalty bonus, RW card at RM position = yes
7 chem, 100 team chem, 433(4), Loyalty bonus, RW card at LW position = No
6 chem, 100 team chem, 4231(2), No loyalty bonus, RM card at RB position = No

There are some variables in here that I couldn't eliminate. After 9 chem, I moved him to RB to achieve the 6 chem test. To get 8 chem I then changed his position to RW, playing him at RM.

7 chem was the most difficult. I had to change his card to RW, change formation to 433(4) and also give him a loyalty bonus. So one of these other changes may have caused him to not be able to do the step over. More testing is needed to eliminate these variables.

EDIT: Khubulov cannot do the step over with a Maestro card applied and 10 chemistry, despite having 2 dribbling chevrons.