CX2 should not transform things like – into their numeric equivalent - because they are a lot less understandable.
Example on frwiki "Félicie de Hauteville" : original translation
- (c. 1078 - c. 1102) compared to (c. 1078 – c. 1102)
- (c. 1070 - 3 février 1116) compared to (c. 1070 – 3 February 1116)
- (avant 1101 - ?) compared to (before 1101 – ?)
- (1101 - 1er mars 1131) compared to (1101 – 1 March 1131)