Pose problem

I've been working on simple stands in DAZ Studio - a T-pose followed by 10 frames of static pose. Every joint except the head and neck has been moved from the T-pose. The hip joint is rotated a few degrees from horizontal.

No matter what I do, the arms give a little jerk outward and back before they move to the animated position. If I don't use 100% IN and 100% OUT, the arms go into the full T-pose, so the first frame of the animation isn't being ignored at all! I can minimize the motion by using an ease-in of exactly 0.8 seconds - any less or more and the motion is more obvious. This happens both when playing the animation alone and when it's put in an AO.

Is there something in DAZ studio (v2.3) that could be causing this, or something I'm doing wrong? I'm using:

15 fps, 10 frames, 1st frame T-pose
Priority 0, looping
IN 100%, OUT 100%
Ease-in: 0.8, Ease-out 0.4

If it's a static pose, you don't need ten frames. You just need two. The t-pose and your static pose. A fully looping pose should be In 0%, Out 100%.

The problem could be (a) unbroken spline between the first (t-pose) frame and second frame prior to upload (b) a bug that SL has for handing any looping other than full 0% to 100%, or (c) victimization by SL optimization (which usually happens with subtle movements, but perhaps 9 frames of no movement is causing a choke). Whichever it is, for your static pose, I bet just having the two frames solves it.

I've concluded it's a DAZ problem. When I upload the bvh file into Avimator I see an additional T-pose frame at the beginning. When I remove that frame and save the bvh file from Avimator, it works perfectly.