Hi Hugh,
in order to compare your graph with the total ARAS EW monitoring, I have drawn it for the same time section as yours. As you can see, there is an certain agreement of the variabilty in your diagram to ours.
The deviation of yours to the ARAS monitoring is caused maybe by the clear lower spectral resolution of your used spectrographs. The integration interval of EW determination of the ARAS monitoring is between 6551 to 6573 Angstr. The accuracy of the EW measurements is (+/-) 5%. Could you say something about the interval and the accuracy in your diagram?
Ernst Pollmann