Sure. If you need 3 ml/roll, use 3 ml/roll. But do this at the normal concentration, not a higher concentration, so you use (say) 350 ml/roll of diluted solution at standard strength instead of 225 ml/roll.
I seriously doubt that ANY developer at normal strength will exhaust if there is enough of it to cover the film, though I wrote to one of the inventors of Xtol about this and was told that yes, it could; without, however, any explanation of the chemistry. I remain suspicious.
I am also suspicious that most Rodinal recipes rely on a wild excess, even after oxidation, and that minima are to allow for VERY high oxidation of the developing agent.
Remember: you need only tiny amounts of developing agent. Consider a Polaroid 4x5, where a teaspoon of dev suffices for pos and neg, or a 2-bath dev where all the developing agent is in the first bath. The rest is normally just to wet the film quickly and evenly.
Cheers,
R.