A couple of points popped out while reading the original post. First, if I’m not mistaken, a hydrometer is calibrated at 60°F, not 68°. So you may want to look closer at your calibration procedure. Also, are you using an accurate conversion calculation when measuring with your hydrometer? I use the calculator that comes with BS. It’s pretty accurate.
Second, I have to agree with Kevin. As a BS user for many years and countless batches, I can tell you that an accurate Equipment Profile is paramount in achieving your targets - all of them.
Third, I’m not familiar with the Brutus system, but I can tell you that the boil-off rate (among other environmental considerations) depends on the exposed surface area of the wort and the vigor of the boil. My boil-off rate is 1.5 gallons in 60 minutes. My boil kettle is 18” in diameter and my burner is 72,000 btu. So, if your boil kettle is larger than 18” and your burner is greater than 72,000 btu, than a boil-off rate of 2 gallons is highly possible. This information is added for reference only.
Fourth, while I believe you need to concentrate on dialing in your Equipment Profile, you may also wish to contact the manufacturer. As a previous contributor to the BS forum, I learned that many brewing equipment manufacturers realize many brewers use BS and have already developed an accurate Equipment Profile for their Equipment. Worth looking into.