I've seen this symbol on several different Mercedes-Benz models. The best answer I can come up with in a Google search is that it means they were sold at the Mercedes-Benz of Alexandria (in Virginia). To me, that makes sense, because I live in the Washington, DC area, close to Alexandria. However, if you don't live in the DC area, that may not be the correct answer.
It is 4 times 320 = 1280
80, 160, 320
320
320.
320 thousands
50 percent of 320 = 16050% of 320= 50% * 320= 0.50 * 320= 160
2% of 320 = 2% * 320 = 0.02 * 320 = 6.4
35% of 320= 35% * 320= 0.35 * 320= 112
45% of 320= 45% * 320= 0.45 * 320= 144
27% of 320= 27% * 320= 0.27 * 320= 86.4
110% of 320= 110% * 320= 1.1 * 320= 352
21% of 320= 21% * 320= 0.21 * 320= 67.2