Considering my father-in-law has been running about a 15K OCI (part of which qualifies as "severe") in his '03 1500HD (6.0) for the last 2 years/70,000 mi. - on syn blend Maxlife - I'm gonna say if you rack up the 15K in less than a year and your driving regimen is anything more than that of a taxi, it shouldn't be a problem.
FWIW, his truck now has somewhere over 275K on it and runs very well. I've been in the passenger seat when he put the accelerator to the floor in low range on his gravel drive, with my 3-ton camper behind us, and I'm still in disbelief that it didn't break something.