MPEG-4 B-Frame Decoding lag removal causing incorrect timing

[sswroom]

I have found that BSPlayer 0.86 build 499, 1.00 RC1 build 800 and 803 have been removed the B-Frame decoding lag such that playing 120fps AVI with B-Frames and Drop frames gets incorrect frame timing. For DivX, it is possible to solve using "Smooth Playback" to obtain the correct 1 frame decoding lag. But for XviD, I can't find any solution for such incorrect timing.
There is no such problem 0.86 build 496 and before.