FWIW, the VYMD AIP entry (not Jepp) has the same outbound timing labelled so that it is unambiguous that the timing starts passing MIA (not that was really in any doubt).
http://www.ais.gov.mm/files/pdf/VYMD.pdf That does not, however, solve the issue that you go outbound in a cat C aircraft at 240kts=4nm/min*1.5mins you'll only get 6nm…..