milage

We have premier and my husband works construction and gets 1099 for use of his truck. He calculates his miles every year. The way I read this is that starting mileage (got that). My question is the miles driving for job, he has that calculated, however when it ask about commuting miles, my thought is that they are going to subtract the commuting miles from the miles driven for job. If that is the case and we did not put the commuting miles in the figure for miles driven for job, should we increase that amount by the commuting miles? This is a little confusing, Any feedback would be appreciated.

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