The first thing that you need to know is that AncestyDNA's database is much, much deeper than 23andMe's. So Ancestry test results are probably more accurate.
Second of all you can not take the countries on these DNA test literally. The results are really for regions, rather than Countries. The significance of that is that Africans lived in Kingdoms, but when the Europeans colonized Africa and created Countries the lines of the Countries cut across Kingdoms. So you have to think about these test results in terms of region rather than Countries. So getting a high result for Ivory Coast/Ghana will mean that you not only have DNA in Ivory Coast and Ghana, but you also will have DNA in Liberia, Sierra Leone, Mali, Burkina Faso, Guinea, Guinea-Bissau and Senegal.
AncestryDNA Regions
Liberia and Sierra Leone came into play, because the Mande people went on something called the Mane Invasion into Liberia and Sierra Leone when the Kingdom of Mali went into decline. The Mande people were already in Ivory Coast, Ghana, Niger, Guinea, Guinea-Bissau, Gambia, Mauritania and Senegal before the Mane Invasion because of the their military, Dyula (Juula or traders) and Marabouts, but that invasion took them into Liberia and Sierra Leone.
Finally, your test results from 23andme has not assigned a region yet. It just shows you the region that are out there. Eventually they will put you in a region like they did for me, which in my case is Ghana.