hai.

it depends on the aptitude of the students as well. there are many mba colleges which offers dual specialisation and many not. 

in dual specialisation you are studying two different subjects for example suppose you need to study total of 15 papers and you choose marketing and finance as your dual course here you won't study the full potentials of either marketing or finance. 

before choosing check the subjects there are few subjects which can be learn by yourselfs in that case it is better to choose dual.

thank you