simotion setting problem?

hello,I meet an urgent question :

when the 3 axis are synchronized to 1 virture axis with a fixed setting velocity value,my problem isas below :
I traced each axis speed curve,found that wave fluctuation is under 0.1/60 Degree after my optimization work,but the tension between each axis(paper) are not stable,

[schnippschnapp]

The last question ,in which condition,can the following error of one axis not be traced ,as a straight zero line.Is the scout version or simotion setting problem?
other questions are splitted to
why the axis synchronized not accurately .
when the virture axis speed up,those tension also changing quickly.
who can give me the proper answer.Thanks a lot!