Dear Brother,
I own Corolla 2007 Xli and its ac is running very good. Gas recharge is normally not needed in the event you described. Mechanics really want to dodge you to make extra 1500 - 2000 Rs. What they do attach meter and will declared that gas is low you while there is not. Beware of them. Don't give them such feeling that you don't know anything.
All is needed to clean fan blower, Evaporator and condenser. Evaporator is above the foot place on no driving front seat. It is definitely chocked with dust and debris. Only get it cleaned first. Job price is 1500 - 2000 depending on your bargaining skills.
Tell the technician clearly that gas is exactly filled and don't interfere with gas pipes and valves. What they normally do is when you are busy some guy make your compressor gas release to make money. They want to hand over you bill of 4500 - 5000 rs in your hand.
AC gas is not easily leaked even 10 - 15 years of heavy use. Its the idiots who make people fool. If your car has any accident and front is involved then gas can be leaked otherwise NO.
AC gas quality is very strange issue. Consider it cheap like cheap painkiller one company is selling at 2 rs per tablet another is selling at 25 rs per tablet. GAS quality is I believe same.
Carbon Tetra Chloride or acetone is for cleaning purpose before welding evaporators and condensers.
If compressor or fan don't start then there is small relay worth 80 - 100 rs need to be replaced.
In Lahore most technicians are fake , lame and "Chuuraay".
Everyone is Zardari these days and cursing only him. You know what I mean. I even don't like him either or his followers.
Be ware of Zardari -Type mechanics.
OmRON