Libre Office 4.0.4 for Windows still has a bug when printing labels. I tried to use the Libre Office writer to print labels on the Avery 5160 form, and the labels were printed in the wrong place. I had to use my old WordPerfect 8 to print the labels.
If you think this is a bug, then please report problem on bugtracker: https://www.libreoffice.org/get-help/bug/
You did not say how much LO is off. 1mm 10 mm or so
I am having an alignment problem as well. The form for the 5160 label seems to be off by a bit. I had to adjust the following.
Horizontal Margin from 2.75" to 2.77"
Left Margin from 19" to 22"
I read in another forum that someone adjusted the following.
Top Margin from 0.50" to 0.51"
Horizontal Margin from 2.75" to 2.77"
As an initial work around for my problem I put a space before every line on the label. I wasn’t doing a merge though so it was a simple fix. Depending on your situation it might not help.
All I can suggest is playing with the margins like I did to get everything to line up.
I think your left margin should be 0.19" to 0.22". All your changes are between 0.01 to 0.02" which translates to 0.254mm to 0.508mm. This is so small that I would easily blame it on the printer.
THE PROBLEM IS THAT LIBREOFFICE DOES NOT HAVE A TEMPLATE FOR AVERY LABELS. I SHOULD NOT HAVE TO ADJUST MARGINS, IN FACT I TRIED THIS AND NOTHING HAPPENED? MY LABELS ARE ALL OVER THE PLACE. LIBREOFFICE JUST NEEDS TO SET UP SOFTWARE FOR AVERY LABELS IN THEIR PRODUCT!
Maybe taking a look to documentation can help:
https://wiki.documentfoundation.org/Documentation/Publications#LibreOffice_Writer_Guide
Writer Guide: Full book, for 4.x, page 160.
The FAQ “How to use private fields in the ‘Business card’ wizard” is also helpful – for what appears to be quite a complex scenario!