[ericbsmith]

The "to owner::tag" needs to be outside of the maths. Try this:

gives(-@int(owner::dr/3) to owner::dr)
gives(-@int(0.4999 + owner::dr/3) to owner::dr)

The first will take 1/3 the DR, drop fractions, then subtract it from the DR. The second will take 1/3 the DR, round up, then add it to DR.

So DR 5 will result in -1 DR in the first formula but -2 DR using the second. DR 6 will result in -2 DR using either formula.