Avery 5160 label definition does not print properly
I've not tried those particular labels, but I had a similar problem with Avery J8160 labels. I started off with a MS Word template downloaded from Avery to get all the spacing values, but had to make some adjustments to the label format, which I did by trial and error to get it printing correctly. I calculated the horizontal spacing as 0.25 cm but had to use 0.45 cm and for vertical spacing@ Calculated 0 cm but had ti use  0.15 cm. Will be different values for your labels buy that gives you the idea. I don't know what wasn't right, but this solved the problem for me.