What is your average moisture loss in a drum roaster when doing an espresso roast that goes for 13 to 14 minutes and stopped right before or right at second crack with Brazilian, Guatemalan or similar bean?

I've been experimenting with longer roast to replicate some drum roast profiles using my air roaster even slowing the air down to where the beans are just barely keeping a steady movement, 19% to 20% is about my norm. If I slow it down much more, I'm thinking the roast is probably going to start getting uneven but 20% seems like a lot of moisture loss. With my norm 11-12 minute roast I normally did, it was never more than 18% and most of the in the 17% range.

I'm losing most all the flavors in the beans and they just take like a plain Jane coffee and thinking that's probably a lot of the reason.

Running some Costarican in a Toper 10K, about 1~1:30 into second crack I was at 17%-18% loss on 2 different 12# batches. Rapid run to turning point, reducing the gas at a minute past turning point and trying to really slow down the 1st crack to 2nd crack progression. Total roast was like 12 minutes or so.

Thanks, that about what I figured I should be getting. If I'm gonna try and copy a drum profile, I've got to figure some what to get my percentages down about two more percent.