When I asked for input from "others", I kind of meant besides you.
However, those are some good examples for helping me gain further insight into what the old planner meant by "vent cooling". For that first example, the old planner shows cooling of 0 (5), though I'd need to search decompiled code to find the logic it uses to determine that the component heat vents should be treated as having 0 vent capacity in this design. If I move things up and place a dual uranium fuel rod below the reactor heat vent (and use pulse configuration to make sure it stops before that vent breaks):
The old planner shows 17 (17), matching my planner. Is that what you meant by "changing components"?
The second example shows 0 (148) in the old planner, and remains the same if I remove all the component heat vents, which gives me a clue where to look.
The third example shows 0 (80) in the old planner.
On the other hand, one could argue that Talonius's planner is obsolete and shouldn't have to be matched exactly. Based on your own words:
I think the key word in Omicron's post is "capacity". Here, it should mean the ability of venting heat.
and https://wiki.industrial-craft.…title=Component_Heat_Vent a component heat vent can reasonably be considered to have vent capacity of 4 per coolable neighbor (other vent types, exchangers, or coolant cells) - it has the "ability" to vent that much heat, even if it never uses it.
Edit: looking at the more complicated design you posted on GitHub:
I think I'm starting to understand your manual calculations and what you want "effective vent cooling" to mean, but trying the closest approximation I can get in the old planner ( 21p7gjnnw20e91es8hy61d1c8mbcxzt9gitwjy3qlgkgbzr5pmf5mgmenu0v2cwebkf9i6v3l3tfcw0 ), either the "vent cooling" shown meant something different than what you're looking for or its calculations are buggy - at 0 initial hull heat, it shows 451 (608) vent cooling, and at 8400 initial hull heat, it shows 644 (664) vent cooling.