Yes we have multiple charts using a site column (versus a list column) as a look-up. In every case the pre-defined choices for future CY Quarters (e.g. CY 2014 Quarter 4) show on our charts while the data list the chart is consuming does not have a corresponding record with the choice. In the interim we have reduced the site column to contain only up to CY 2014 Q2; at least this way – depending on how up to date the data in the list might be – we only show two or three blank columns on the chart – and fortunately they are always at the end of the x axis.
We are not using 2 data lists for any of our charts. If you want, I can provide login information via e-mail so you can view our live site. The other design choice we've made is that for the public side of this – we are using list columns to maintain the CY Quarter choices. I attached a template of the list which generated the chart in the prior post – the CYQuarter column is a site column.
Regards,