When i try to roast back to back roasts the second batch roasts much different, and a faster roast. not sure why the roasts are the same time to complete.
The bullet got heated up on the first batch.
You can mitigate that with doing a preheat of 310’c and leaving it there for sometime (I usually leave it for 15 mins after I get the charge) then cycling and putting your desired preheat.
I usually charge 900 grams at 300 C preheat, which is usually around 212 C bean temp. After each batch, I let the bean temp drop to 140 and from there I raise it back up until it stabilizes at 210 once again. I found this works quite well and I don’t have to play too much when I’m roasting each batch to try keep the same curve.