I have to agree. The combination of the thinning/rifleing of the copper tubing in the fin packs, the tightening up of buildings that prevents fresh air exchanges and the introduction of more VOC's through building materials and scented products has resulted in more coil leakage over the past decade.
Training is important!
Practical Training is a must!
Ran into as many leakers before they made the copper thinner as now.
It kind of runs in spells.
I'm not explaining, I'm just complaining.