OK, I have just replicated what you are doing. You have a fundamental misunderstanding of how to plot a VOR radial!
If I draw a line from BEL to EGAE and measure true course, I get 305d add 6d from the variation on the chart and I get your 311d radial.
If I use the radio nav plotter from my Jepp IFR kit on the flute on the VOR radial I get 314d.
The VOR station is corrected for the variation at that point. The chart gives an average across the variation lines.
You should not plot VOR radials in true and convert you should take them straight from the flute as this is the information displayed on your instrument.