I'm having problems with pre-boil gravity (and possibly volume) predictions. Most recent was using this recipe on the weekend - https://www.brewersfriend.com/homebrew/recipe/view/1045967/bnp. I was spooked when I entered the pre-boil numbers, as it seemed I'd missed the pre-boil prediction by 12 points. The recipe predicts 1.060 and I'd hit 1.048. Though the efficiency numbers on both conversion and pre-boil were completely in line with expectations. So I ignored it at the time and started the boil. At the end of the boil I find I've hit my OG of 1.068 and the correct volume of 7 litres. So it's looking like the pre-boil prediction is off. When I entered the pre-boil log entry I noticed that it was expecting 8 litres. Which explains the the 1.060 number, as that's what this recipe would be with 8 litres of volume and the 75% efficiency. Though I've no idea how it's decided that the volume would be at 8 litres at pre-boil. It should be at 10 litres as I'll boil off 3 litres for the final 7 litres of the batch size. And 10 litres for this recipe at 75% efficiency should be more like the 1.048 I actually achieved. It seems like the pre-boil gravity prediction is assuming I'm only doing a 20 minute boil.