Normally car AC system has two options:
either to suck fresh air for cooling
or suck the air from insid of the car.
AC system produces more Cooling in case if it sucks air from inide of the car. because system is sucking already cooled air for further cooling.
Evaporator/cooling coil has two sides one towards the engine bay and other is towards the interior side.
Also if Evaporator/cooling coil is not got cleaned afetr one or two years then its inner side becomes clogged with dust and it blocks the air passage. Its cleansing results in enhanced air throw and effective cooling. Inner side becomes clogegd/blocked with dust beause when cooling system sucks air from inide of the car then this air thru the cooling coil and its dust etc becomes stranded in the jaali of cooling coil. That why....
get it cleaned your air throw shall be enhanced.