We currently have a single entry covering Bangladesh 5 taka P#53 and P#53A. However, as someone has already added to the comments, P#53A needs it's own entry as these two notes are significantly different, as can be seen here:
http://banknote.ws/COLLECTION/countries/ASI/BDE/BDE0053.htm
http://banknote.ws/COLLECTION/countries/ASI/BDE/BDE0053A2.htm
Indeed, the difference between P#53a and P#53b,c (most notable in the portrait) should also justify separate entries.