Why are some car specifications quotes at numbers like 1.10lbs+.15?

the system has tolerance to work according to climate and altitude

It is so do it your self will not temp to work on the system. The max the system can hold is 1.10 oz plus .15 oz. A .10 or .15 can is not out there. It is done by weight the fill tank before and after. And using the low and high side reads to properly adjust the charge so it does not over fill the system. A over filled system can blow it apart in side. This were the shop get their major work to repair the system after it been over filled. These are high dollar repairs from those did not know what they were doing. Though the system was not coolant when it was putting out it's max dure to the weather. I little open at the top of a window will let the heat out of the greenhouse. It is the same with a car with all the windowers closed. When it get's over 95 degrees it is hard to cool a car like your home. Even some home cannot be cooled when the temper get's to high, That don't have a fan to remover heat out of the house. I can remember when there was no air condition. It was a matter of using fan and open windowers at the top and botton. The house was cooler than out side. You got your body adjust to the heat. They think they cannot live with out it.

That means it'll take up to .15 of a lb more than 1.10-lbs.