In theory it sounds simple but have to agree even with more frequent oil changes, it seems one would not be correcting the oil content and getting out all of the engine wearing grit.
Having the oil tested to find out how well this method is doing is an excellent idea, one I'd promote should someone want to try this plan.
And I'd do more indepth research. On a rig that is still under warranty...could be the manufacturer's warranty could be voided.
One thing I find curious...if he has had to add one quart per 1000 miles since the engine was new...is there indeed an issue he should be addressing to reduce oil loss? We've not had to do that with our DP.