I find that, too, but I think it's because my subwoofer and lower group of full range speakers were balanced against my middle and upperwork audio groups using a few SP samples such as Caen, St. Omer, and Rotterdam.. Then I found that Lavender and Milan seem to have much higher bass levels, while OAM has lower bass levels, so I have to change rank levels on some of the 16 and 32 foot stops including manual 16s to avoid unbalanced sound.
I only have 3-4 samplesets from each except SP, so not a comprehensive survey, but so far the bass levels seem to differ more between producers than between their organs. So maybe a microphone choice or placement, or an editing preference.