Their scale only goes up to 1%. They have never seen cannabis with even 1% Ca.
A&L has a much higher range. I did some tissue analysis in 2013/14 and Calcium was around 4%. I think these were the years where I was starting to get Ca up to 70-75%. K was still high in the soil and the tissue was at 5.5%. I haven't done a tissue submission since then. The guy made a comment on how bad the "hop" leaves stunk up the lab and it made me too nervous to bring more in.
ask them to review chapter 20, especially pages 160-161.
Handbook of Reference Methods for Plant Analysis
The Horiba Calcium meter does the same thing for me. I have to dilute 10x at least.