I've mailed Brad a bit back and forth about this. And unless there is something in the conversation I misunderstood the only temp-correction BS does is from boiling down to pitch-temp. I've had a time where I was calculating thermal expansion left and right until I just didn't care about it anymore since there are other factors affecting the volume in much bigger extent then this.

So when it says "add xxx of water at xxx degrees" it doesn't take into account (approx) 3% thermal expansion at typical mash temperatures. If you measure volume at mash temp, you should subtract the given expansion relative to ground temp.

Anyhow, this shouldn't amount to 0.4 gallons, unless you brew big.

The simples solution would be to go into options, click advanced and adjust the grain absorption. If you have 0.4 gallons to much, just calculate it down to fl oz/oz (of grain used), and subract that number from the number already in the grain absorption box(es). But it's worth noting that this is not linear. Bigger grist sizes will give you a bigger pre boil volume, for some reason I don't understand, but only have accepted.