By definition, a reference dimension is ALWAYS exactly correct (i.e. 1.020 in this case). However, what your customer MAY be looking for is the deviation of the profile in one direction (for example, (presuming it is a bilateral callout) it may be more advantageous to have the profile towards the low side, rather than to the high side. Best idea is to contact your customer, and determine what it is that they are actually trying to control.