User blog comment:Kitahara/Recording drum expedition success rates/@comment-25730832-20150206083101/@comment-25832576-20150214220544

Homu:

The title in the table is a bit of a lie, I used 3x drums on each ship for exp 38 BUT I did exp21 simultaneously, except with only 2 drums on each ship (which is effectively 3 less 'additional' drums after taking into account min. requirements) due to going on a drum scrapping spree a long time ago and not having enough to fully equip exp21. But it made for a good side observation so no regrets.

Melon:

Yep measuring by quartiles is a good idea. Measuring drum by drum would take too long and the differences between each single drum would be rather minute/hard to tell.

Explaining things coherently has never been my forte >_> My hypothesis was the GS rate starts at 15% once you meet minimum drum requirements. So 3 drums in exp 21 = 15%, and 8 drums in exp 38 = 15%. Then from there, extra drums add an unknown amount of % per drum, possibly up to a certain limit.

Using my records as an example, exp21 had 10 drums equipped and needed 3, so that's 7 additional drums while exp38 had 18 drums equipped and required 8, so 10 additional drums. Obviously that would mean exp38 gets less additional % from extra drums, since it needs so many for minimum reqs (assuming there's no cap on this bonus).

But the only reason I came up with that is because it always seemed to be exp38 that people were failing with 6 sparkles, leading to me to suspect extra drums made less of an impact there. I've done jack ship for recording the base rate of 38 for now, so there's still the possibility it might not consider minimum requirements at all.