Inferred R_p/R_∗ offsets for wavelength bins of using 20 nm width. Top: results from separate analyses to each epoch, where blue, red and green points refer to results from 27 June 2015, 10 July 2015, and 03 May 2016, respectively. Bottom: results from the combined analysis of all data (black points), together with the 2 nm bins centered on the Na and K features. Results from the separate analyses are shown in gray.