TTV amplitudes reported by Mazeh et al. (2013). The dashed line denotes a linear fit to the maximum amplitudes for TSNR = 30 (see Fig. 5). The points marked with X are found to have periods related to the stellar rotation; all of them lie well below our predicted amplitude maximum caused by spots. The points marked with triangles are taken as spurious which could have been caused by other sources capable of inducing TTVs (i.e., sampling or eclipsing binaries).