There is no Malaysia Standard for the wiring size between the Outdoor and Indoor unit, only the installed wires that feeds the a/cond. The wiring between ODU and IDU is considered wiring internal to the unit and is specified in the installation manual by the manufacturer.

Sample of specifications from Daikin


40 x 0.0076 = nominal diameter 1.1 mm²
70 x 0.0076 = nominal diameter 2.0 mm²
Looks like 40 x 0.0076 should not be used as I have never seen an installation manual that allows less than 1.5 mm² between the ODU and IDU. For the 70 strand you need to check for your specific unit if it is appropriate.

There is no absolute pressure that a unit has to be. The proper pressures are confirmed by SubCooling (if TXV metering device) or SuperHeat (Capillary or piston metering device) Your a/cond may or may not be working properly at your stated pressures. The point is, a tech cannot simply say need to increase the pressure without checking SC/SH

15 m of copper pipe PER ROLL (50 ft) x 2 roll (gas+liquid) about RM 450. Need 3 x for your distance, so copper alone RM 1,350. Insulation is per 6 foot length at RM 3 per length, so RM 75, 4 wire 2.5 mm² (because inverter, and far away) per roll about RM 400 (90 m per roll, so can use for 2 a/conds, so RM 200 per unit). So far RM 1,625 in basic material costs only PER AIR COND. So 2 a/cond installation with distance of 140 ft is RM 3,250 in basic material cost.

Your quoted installation cost is cheap. Please check if there are any hidden costs, or if substandard material is going to be used, or if the installer has made a mistake. After started already and then they will come and say have to increase the price.

But forget all the above first..... I believe that 140 ft is over the maximum design limit of copper pipe length for most domestic air conditioner units. Your air conditioners won't work properly, if at all, if my opinion is correct.
Check the installation documentation of your a/cond model to find out the maximum distance between the Indoor/Outdoor units and only proceed if it is within the distance. If not, please redesign your layout.

Oh crap, disregard all that I wrote, I misread your post. I re-read and you've written like you have already done and paid for this install, so.....

Would you be happy if I said the cost is cheap and you got a good deal? What about I said it is expensive and that you got conned?

The fact is the installation is completed and you have already paid. Move on with your life and don't revisit the past that is already done.

Yes it does make sense, but depends on the actual area you have, and what temperature you set the a/conds at. If the cold air keeps escaping, or if the temperature you set is too low (and the a/cond cannot reach that set temperature) then the a/cond will be running at full power, and you will not see any savings compared to a normal unit. Does my explanation make sense?

That is correct. Think of it this way; minimum speed limit is 160 km/h, but you drive an Axia. You're going to always be pedal-to-the-metal full throttle to keep up to that speed, but a bigger cc car would have reached that speed, and be feathering the throttle to keep to the speed.

Similarly, if the cold air keeps leaking out from the area, or the area is too large, or the temperature is set too low, or you keep putting hot air back into the area, then the a/cond is going to be at full power all the time to reach the set temperature. So no benefit for having the inverter.

It's not safe. The lizards will crawl onto the PCB and get electrocuted, and then the a/cond may not work or you will have bad odors. I've had to repair a few circuit boards already where this has happened.

This one you have to clever clever yourself, I can only answer on the electrical safety question of ItsJustheOne

I can do it cheaper than that price, but do you think I want to travel to your place to do it?

That's a good experiment to try. A capacitor costs about RM 18 - RM 25 only. Let us know the results after you change it