There's no such thing as maximum velocity. If constant 1g acceleration is available, there's not really a fuel concern. It will certainly use a little more fuel

There's no such thing as maximum velocity. If constant 1g acceleration is available, there's not really a fuel concern. It will certainly use a little more fuel, but even just going to Mars would take a week, so half an hour's extra fuel usage works out to 0.3% extra fuel. For interstellar journeys, you're talking less than 0.001%. Also, the course correction can easily be part of the manoeuvre, if you're willing to rotate around more than one axis.