There isn't that much difference, energy wise, between a "comfortable pace" and a "maximum climbing rate" that you can maintain for 30 min. 180 W might be "comfortable" and 250 W might be the maximum sustainable for 30 min. The difference is mainly that, in many cases, you have the gears to go at 250 W @ 80 rpm, but you don't have the gears to go at 180 W @ 80 rpm. In this case, trying to be "comfortable" is counterproductive.
However, on the target rides themselves, climbing should be done at a comfortable pace. Working at a maximum climbing rate burns energy much faster and requires more recovery.