As I said above, I don't necessarily disagree with the idea that it takes longer to pad open holes than closed (the first point you made). I don't find it to be so, but it's understandable that others might. I do, however disagree that open holes are more delicate and precise to pad (the second point you made). I believe that you pay more for the open holes than for a closed hole flute, but not knowing your tech, I have to assume that there is some deeper reason for that charge. Perhaps he does find that it takes longer to pad an openhole flute than a closed hole flute, which could lead to more worktime, and thus the charge. Or perhaps he has some other reason, but that charge almost certainly does not exist to cover more precise work, as Plateau flutes need to be padded just as precisely as open hole flutes. I'm not trying to debate how long it takes to pad different styles of key cup, just the idea that one requires more precision than the other.