that's what the bug was that was fixed. if you had a custom nation, any of your modifiers for said custom nation (e.g., culture conversion cost, or tech cost, or core cost) was applied for each time you clicked a button, and said attributes were recalculated each month (and when wars ended, and a few other reasons, such as coring or taking the actual tech) so you had to click a lot but you could queue 1000 ships and end up 400 years ahead of time on tech rather quickly. or, you could culture convert everything.