This has been a very good discussion. The statement I quoted is in the maintenance manual that came with the genset, thus your Cummins service advisor is not likely to give you any advice other than "go by the book."
A good guess on what is going on is a remark by one knowledgeable person. The engine has to comply with EPA emissions rules. It may be that this maintenance is needed to guarantee compliance. I'll go forward assuming that this guess is correct, and will not suffer any pangs of conscience by not spending $1000 for this guarantee. Afterall, I mostly run the genset when overnighting at a truckstop or WalMart parking lot.