I think you need to clarify if you are talking about the 1/1 (full) turn, right after she comes up off her knee and before the hitchkick, or if you are talking about the leg swing 1/2 (half) turn, right before the balkwalkover.
Gymdog is correct if you are talking about the leg swing 1/2 turn. This is not an element with value, and the deduction would fall under general execution of incorrect foot form, only .05 each time poorly executed.
If it is the 1/1 (full) turn that is a whole other ball of wax. The element is worth .4. It is up to .1 in general faults and penalties for "failure to perform 180* & 360* turns in on one foot in releve. There is also an over turned deduction stated as "Degree of turn not exact (over-turned)... up to 0.2."
In optionals there is a degree of incomplete turn deduction, but I'm not sure it applies to compulsory L5 & L6. I tell my girls it does because I want them to already be in that mind set (a little coaching white-lie), but I see no reference to it in the Compulsory Code of Points that is open on my desk right now. In optionals if you fall out of your turn, i.e off your toe or step down, before 3/4 of the way completion then you lose credit for the element, which is a biggie for L7 as it is a Special Req't. I hope that is an accurate description of that deduction, as I don't have the Optional Code of Points on my desk right now. If they do make at least 3/4 before dropping the heel but not the complete turn, then there is a range deduction of 0.1 - 0.3 depending on how severe.
Again, that last part is for sure for the Optionals, but honestly I don't see reference to it, other than what I quoted above and it specifically states over-turned, in the Compulsory Code of Points. If anybody knows for sure then please feel free to clarify. Or I could get off my butt and walk downstairs to fetch the Optional Code of Points... hmmmm, not time to go down there yet.